Honda Classic Racing

new project

2012-01-09T13:37:00.001-08:00

As if I didn't have enough projects, I started a new one, just to use some of the parts I have gathered over the years for the cancelled CR110 replica project.

It will be an 85cc racer for the SAM 50cc class (4strokes are allowed to have 85cc)

first time outside, the lengtened swingarm was just ready, made from a CL90 swingarm, now with needlebearings. Long wheelbase like the Van Veen kreidlers back in those days.

I plan on keeping it pretty simple, mostly using parts I have.
Also, the project is for sale, would somebody want to buy it and finish it themselves. That would give me more time for other projects.

CB50 caferacer

2011-12-08T10:04:00.000-08:00

A bike I built, rode and then sold. Sometimes I miss it, it rode really nice, pretty comfortable, quick and it looked pretty cool.
Very retro 80's caferacer with magnesium wheels that just about everybody in the dutch 4-stroke community hated. I think they were just accustomed to the spoked wheels of the SS50's.

this is pretty much how I bought it and rode it for a while, the only modification by me were the sporty handlebars. It came with the giuliari seat.

Starting the transformation, this is a picture of one of the first complete mock-up's
When I bought the bike, it came with a lot of extra parts, including the tank with Bultaco stickers, I originally planned on riding it like this, just to piss people off with my "bultaco"

And the endresult, I changed the exhaust endcan later on, so the bike could breathe better, but I have no nice pictures of that.

some specs:
-ktm magnesium wheels
-CB750k1/6 front brake caliper and master
-50cc (still a legal moped)
-5speed xr80 gearbox
-CB50F camshaft
-16mm kei-hin carb
-slightly ported head and rounded valves
-adjustable clipons
-Ducati seat
-homebuilt rearsets with 10mm spanner as shifterpedal

C110 racing cam

2011-11-27T12:03:00.000-08:00

How can you get more power out of a C110 engine? Fit it with a racing camshaft.
Only one problem, racing cams are not really available anymore.
I've seen some adds of old american aftermarket suppliers that had cams for Honda's including the 50/55cc OHV engines, but have never run across these camshafts for sale anywhere.
Luckaly my dad has some experience in making his own camshafts.

The C110 camshaft in line with a BMW R50S camshaft that will provide the profile.

Grinding stone, grinding away the C110 camshaft, this will result in a smaller ground cirkel, but also a higher lift and longer duration.

Finished product, the intake cam is reground, looks small next to the original exhaust cam, but because the groundcirkel is smaller, it is actually an inprovement.
Already made a testrun and you can feel the extra power in the higher revs without losing a lot lowdown.

C110 cam lift profile (not valve lift) compared to some others, the intake cam is now reground to the profile marked 50s,69s, clearly visible that it improves lift and duration.

S90 oilcooler hookup

2011-11-24T13:00:00.000-08:00

The 100cc motor I've been runnning this season has the tendency to overheat after a few laps, So even though I like the empty looks of the frame, I will be fitting an oilcooler for next season.
To look at the options, I started drilling into an original headcover, it had a broken fin anyway, so nothing was lost.
But it turned out pretty well, I have my oilcooler hookup now.

The top oil line runs up because that was where the broken fin was.

I think the new motor wil really like this, as it has a topend based on the ATC110 with cast steel cilinder, something I want to put together over the winter, you can see what it will look like mounted on the empty motor here:

this will become a 122cc motor with CT110 crank and 56mm piston.

What's wrong??

2011-11-07T13:20:00.000-08:00

The other day I just felt like taking some pictures.
I'm not satisfied with the way my SS50 looks now, something about the totall package that just doesn't feel right, but I can't really put my finger on it.
The line of the tank and seat isn't straight enough, or the swingarm is too short, front forks too long.....
Or should I just put original handlebars back on?

long time no blog......again

2011-11-07T13:03:00.000-08:00

Been busy at work and with a lot of different stuff.
My car needed some work, but now I've got brakes again, quite a nice "luxury"

Also took an old CB72 front wheel out of the corner, that before I bought it, had been laying in a field for 40 years.
Skimmed the drum surface just a bit, to hear if any rust had come between the lining and the castwork, but it still sounded good.
Japanese hubs don't have the problems that european sh!t have, but the rustpits in the brakesurface are so deep that a lot of material will need to be taken out, so only for use in a 50cc or 125cc bike. In a CB72 we overcook these hubs anyway.
Narrowed the hub to get rid of some broken edges, but it still needs finishing.

Will probably lace it to an 18" wm00 rim for use in ....... or sell it if somebody is interested.

On the left in the picture a CB750k1-6 carb, 28mm, now prepared for a 1cylinder bike, so I might use it on a 125cc SS50 engine I'd like to build.
Also completed a 26mm Cb77 carb for use on an SS50, just out of view as it is now on the 70cc engine in the background that I might convert to 85cc.
Just some other stuff I've been working on.

bigbore stroker stuff

2011-10-02T12:53:00.000-07:00

I've changed my plans.
I have an SS50 motorcycle (2 actually, but the second one isn't ready yet) and I collected a lot of original 50cc 5speed parts for them, like alloy cilinders and the heads with big fins and ports.
But now I've ridden with a 50cc and a 70cc engine on public roads and I just can't keep up with modern traffic. So I've fallen off my beliefs and started with the bigbore stuff. But still not the kitakkiewakkie-craft, just cheap aftermarket stuff.

I've now built a 110cc SS50 engine using a 52mm stroker crank and a 52mm piston.

specs:
- 52x52 110cc
- Old Type 70cc head with big fins (NOS), ported
- C70 camshaft
- advancing flywheel, 6V ignition
- 2plate clutch with alloy centre
- 5speed gearbox with modified first gear
- 20mm carb (until its broken in, then I might go bigger)

Today I built this engine under my SS50 motorcycle and took it for a testrun.
Nice torque, lots of power, in fact, more than the clutch can handle.
So at the end of the day I took the motor out again, will need stiffer clutch springs and also need to look at a small issue with the gearbox.
But this promises much good things, I allready have plans for a 125cc 54x54 engine.

And another crazy idea, a very much cc old style C90 with the 6V engine.
My S90 has shown these old things can be quick, now I'd like to use one of these old beasts to kick the crap out of some of those modern chinese 125cc+ bikes.
With the parts Ralph has, we could get upto 180cc, or just 170cc with the cranck he would sell to me. but still that is more then the china-crap.
Now just to find a C90 to start the project...... if someone in holland has something, you could let me know.

crappy sketch:

I won't be actively pursuing this project, as I still have a couple of other ones that are unfinished, but this would be a fun quick one.

Veenendaal 2011

2011-09-23T14:17:00.000-07:00

okay, it has been some time ago, and there have been events since then, but this is what happened at Veenendaal this year.

Picture thanx to Lea langezaal
As can be seen, I have a groundclearance issue.

And then this is what happens:

Emergency repairs so I could start the next heat.

more can be read at Ralph's blog, he came to see what I was doing with the engine he donated to my project.
Also a nice video of me just before the start.

By the way, I plan to build different, higher, footpegs for next season, a little less original, but I need the groundclearance. I'll make it look like honda made them by using the right parts.

Coil testing

2011-09-01T14:51:00.000-07:00

I had some problems with the ignitioncoil I used on the S90, it was an old CB72 coil but when it was replaced with a different type, my S90 ran better.
I really did want an original CB72 coil, as they were used n RSC90's back in the 60's and it looks good, so I had to test the coils that we have.
My SS50 was the answer:

I found out which of the 5 coils were good and now have an original CB72 coil on my S90 again.

C110 engine, but not my own

2011-09-01T11:14:00.000-07:00

Been busy with a lot of things, but didn't take much pictures of my own projects,
so here is some of the C110 engine I have been rebuilding for Ralph

Ported head:

Everything glassbead blasted and some fresh paint on the cast steel parts:

Clutch pressure pin / oil guide stolen from my extra motor as the one that was in Ralph's motor was broken. Anyone has a spare?

Kijima ohc headcover in the lathe:

Now it is a cluch cover:

Modified finned tappet covers:

Also a Kijima ohc headcover as a pointscover:

Modifying a webco Z50 intake manifold for the C110 head:

With homebuilt heat isolator.

Taken the flange off, because there was no fitting carb for it, now a rubber flange off an SS50 manifold so we can fit any slant flange carb:

Top view:

It's almost done now, just some special oil line and some gaskets for the manifold and we can start thinking of starting it up and seeing how it runs.

Look what I found

2011-07-17T14:24:00.000-07:00

When wondering around the attic of the local Honda shop, I found a set of original C110 footpeg rubbers, no longer available from Honda directly.
Found these in a bunch of NOS parts they have.

home made rev counter face

2011-07-07T10:50:00.000-07:00

I made 2 different faces for my homemade rev counter, they are based on what I made for my 50 a few years ago. A standard Honda tacho with a homemade CR110 replica face.

I cleaned off all but the scale and made something modelled after some RSC tacho's I've seen on the internet:

This looked a little plain to me, so I also made something with the actual RSC logo:

These are just normal printouts for now, to get an idea of what it would look like, but now I'm not sure what to make. RSC in logo or text....what do you think?

home made rev counter stuff

2011-07-03T14:05:00.000-07:00

The plan: build a mechanical tacho and tach-drive onto an SS50 engine.
terms: do not use kitaco or takegawa bolt on stuff.

I started with a tach drive from a CB175, turned something on the lathe and took the teeth off of an old camshaft sprocket, this should be soldered together with silver and mounted to the camshaft.

should look like this when mounted:

The housing was cut down to remove unnecessary material and to create a hole for the bolt to go through that will hold everything onto the cylinderhead. A brass plug will be put in there with threads to accept the bolt.

One problem, on a CB175 this is on the right side of the camshaft, on the SS50 it will be on the left, so the tachocable will be turning the wrong way.

On the back of the Yamaha 600 guage unit (that I took the tach from for the RSC90) was an angle drive that I could use to reverse the rotation...

Some PVC tubing, a CB50 tach and one Yamaha drive later:

Testrun if it all works...NO?...
I looked at the angle drive the wrong way, so it doesn't actually reverse the rotation.
I will have to make something else to fit onto the modified CB175 drive and use this tacho on another bike when it is finished.
Will be painted black, alloy ring to be turned on the lathe and a piece of plexiglass to close it all up, after I've made a new face for it, probably upto 14000 RPM or a bit higher.

Caferacerdag

2011-07-03T13:45:00.001-07:00

Today the dutch caferacer club had a meeting, so I decided to go and have a look.
It was a nice excuse to take the BMW out again and my dad came along with his Oudshoorn BMW, although not totally complete yet (notice the seat) it was a nice ride to run in this newly built 700cc engine.
The bikes before departure;

The oudshoorn looks small next to my R90/6

To see more pictures of great caferacers that attended, look at the chalopy blog Ralph was there too and took a load of pictures.

RSC engine cover

2011-07-03T13:20:00.000-07:00

Look what came in recently.
Specially made in england by a great guy called Colin Marley.

Original next to CNC milled, I glassbeadblasted mine to match the rest of my engine, and for some extra cooling surface.
Here is what that looks like when mounted, sorry about the fuzzy picture.

Some of these will go to Australia (you know who you are) but I haven't figured out the shipping yet. There is one extra if someone would be interested.

Hondaday today

2011-06-26T11:08:00.000-07:00

Today was Hondaday, the yearly gathering of the dutch honda moped club.
In the morning the weather was almost clear, so I thought I'd give the SS50M a ride to completely break in its 70cc engine.
I totally forgot to take pictures, but Ralph will probably put some up on his blog.
Spoke with Ralph for a while about the C110 engine I am restoring for him and the S90 parts he borrowed me. Had a look around the lot, spoke to some other people too and then went home again.
But only after I had the SS50/70 on the dyno. The Honda club had arranged a free dyno for everybody to try their bikes, so I couldn't pass that up.
Graph seen here with some great pictures from Mischa who brought his 1970's polaroid camera.

About 6.5 HP at the rear wheel, not bad for a 70cc with 20mm carb, with a top of 115km/h.
The bike is now totally run in, so it's time to start looking at the 26mm carb that I would like to put on it.

The right tools

2011-06-19T11:31:00.001-07:00

Finally my tools are in.
Original Honda crossheaded bolts are different from philips or regular crossheads So I ordered the original Honda workshop tools.

This is worth the money, it really makes working on your old Honda easier.
If you want to order them too, the Honda partnumers are:
07603-0050101 for M5 and smaller bolts.
KL1696 for M6 (engine bolts)
It did take a while because the big size was in backorder for a long time, so be patient.

Lots of racing this weekend

2011-06-12T13:32:00.000-07:00

Yesterday we had a race in Nunspeet, I had a lot of trouble getting the RSC running correctly, fiddeling with main jets, but at the end of the day I found the right one. All the symptoms directed me to a bigger jetsize, but smaller was the answer.
I did have a lot of issues with the gearbox though, after the clutch exploded, the gearselector arm was bent.
Pictures can be found thru the Nunspeet bike club website (click "classic race")
What do you know, If you click the 2nd link, the first thing you see is me....

picture thanx to: www.naomischolten.nl
More great photo's can be found on her website.

My dad rode his CB50 with 75cc engine, also having gearbox trouble, first time an original honda 5speed doesn't work the way it should, they are normally pretty indestructible.

My RSC engine was opened up today to fix the gears and it seems to work a little bit better now.
So the RSC is allready on the trailer again for races tomorrow in Varsseveld.
I didn't want to ride the 250 or 500 there, so we got my CB50 out and put it back together again, as some parts were "lent" to other bikes.

I hope tomorrow all goes well, the 90 gearbox should show improvement and the 50 has an experimental camshaft setup.

Cam timing

2011-06-12T13:21:00.000-07:00

The trick to timing your cam the way you want to:

Extra holes.
In fact this isn't my camshaft I'm now using, it is Ralph's But we now have it timed for more power at higher revs.
It was probably made for dirt-track or motocross, probably even for ATC's where you would like to have power in low revs, but for roadracing this could be cranked up to about 11.000 RPM.
I don't want to go much over that, just because of reliability and gearbox limitations.

New seat

2011-06-06T13:14:00.000-07:00

Bought a new seat for my SS50 off ebay.
The old one made the whole bike look very dark and chunky, with a fully black seat with black piping.
This one has a nice "chrome" edge and its a little thinner then the old one.
It is aftermarket, but you just won't find originals.
And this one fits, unlike the aftermarket stuff sold in the Netherlands or the expensive benly seats that also won't fit with a CD50 tank.

Note the breather, just like his RSC90 big brother.

Anjum

2011-06-05T14:25:00.000-07:00

The third event for the RSC90, it was repaired just in time after the clutch thing.
Carb was temporarily replaced with a CB100 part that we knew was working, also the coil was replaced. These were the parts that were doubtfull, so we eliminated them.
A shot in the paddock:

You can see the CB100 carb mounted on an original manifold.
After the training we put in a bigger main jet, it ran pretty well, but the plug was a bit light.
Just one round in the first heat told me that was wrong, I came in, we tried to change the needle position in the hope we could get some progress and I could back on the track for the remainder of the heat, but the clip fell off the needle in the grass.....damn.
But at least we knew now that the bike could run good, and the problem had probably been the coil.
So we put the CR29 back on for the second heat, and it ran pretty well, needle and main jet being allmost right.

Also note the alloy top crown plate from my CR110 replica forks, this was to get less pre-tension on the front forks, a step forward to good handling.
close-up:

A shot from the paddock:

Me in action, must have been the second heat, as you can see the CR29 mounted.

picture thanx to Lea our club photographer.
more pictures of the event can be seen here

the clutch

2011-06-05T14:21:00.001-07:00

....or what was left of it, after we fished it all out the engine.

Note the elongated springs and warped clip.

still busy, and lots of work to do......

2011-05-30T13:51:00.000-07:00

The RSC90 is costing me a lot of time, in finding the right camshaft, carb settings and ignition timing.
I Have had my second event with a standard camshaft, this didn't do bad, however the carb settings were still of...or were they....
Only fault with the standard cam was a worn out hole for the pin that alligns the advancer. This caused the pin to come out and grind against the housing, causing aluminium flakes to mess up the points.
And that was another racing weekend down the drain.

So we decided to put the 90 on the dyno, although the dyno wasn't 100% functional, we could do unlimited testing.

After 4 runs we really didn't have an idea about the carb settings, but in hindsight something must be wrong with the ignition. (probably the coil)
No really clear runs, but at one point we had a max of roughly 10.6 HP at the rear wheel.
I think not bad for a 100cc, now just to get it running correctly so it will become rideable without constantly feathering the throttle.
(The coil has been sent out for testing.)

But then.... a big crunch and strange mechanical sounds.
some oil on the outside of the engine cover, I suspected the clutch.

Back home we opened up the motor, it wasn't so much the clutch, as the lack of...

Aha, there is the rest of it.

And some debris cought the dipstick, now I have to figure out the level again, probably the least of my worries.

So I have some work to do, the engine is out, we're going to take it appart completely to clean it from bits of clutch. and then install a slightly newer style S90 clutch which has just a bit more material so I hope it will be stronger.
And only 2 days to go before it should be on the track again.

been busy

2011-05-18T12:55:00.001-07:00

Late update, as I've been busy with too many bikes and things simultaneously, allmost causing my head to explode at some point, from an overload of information.

The RSC90 had its first event....and a lot of bugs showed themselves needing to be sorted out.
The front forks were too stiff, causing the numberplatebracket to bend en hit the front fender.
The rev counter wouldn't go past 5.000RPM because of vibrations.
Carb settings were way off..
or maybe not, as the camshaft is wrong.

The bike felt really!! strong upto about 5.000RPM but after that, there was almost nothing.
So I borrowed some camshafts from Ralph and my dad started measuring.

After that, a load of graphs to compare, and lucky for me, my dad can read these like a book.

including the original S90 camshaft, we now have data on four different profiles, one cam looks nice for racing use, now I hope Ralph let's me use it......
One of my camshafts would be okay for the 122cc engine I plan on building, if it is possible to rotate the camshaft about 10 degrees, creating different timing.

I plan on riding next sunday with a standard S90 camshaft, maybe I can then get the carb figured out. And test the modifications to the front forks, rev-counter stay and so on.

For those of you who like pictures, this is the RSC in action.
click on the picture to see the album of the photographer.

first event of this season

2011-05-04T11:31:00.000-07:00

last weekend was the first event of this season, I didn't take the RSC90 though, this track was quite long and I want to give the S90 a good chance to have a smooth run in next weekend at Oldenzaal.
In Wolvega I rode the CB72 that I had some experience with last season and one of my dad's BMW's. This was the first time on a 500 BMW for me.
It took a bit of getting used too, especially the speed as I reached over 200km/h on the straight after which I had to brake hard for a 2nd gear corner. But I had fun with it.

picture thanx to Lea, CRT club photographer

No. 64 is me on the CB72, chasing a maico that I passed later on.

Again, picture thanx to Lea.

But I think this picture was taken just 3 corners before the CB72 tried to kill me....
The oil seal in the outgoing gearbox shaft worked itself loose, spraying oil over the right side of the bike, causing me to fall in the only right corner on the track.
Luckaly I could stand up without problems and pick up the bike. Only some bruises to my leg and back.
My ego was okay as this was clearly the bikes fault.

And this is what the CB72 looks like now, taken appart to straighten the front forks, new seal installed on the output shaft, footpeg straightened, but still some more work to be done before I can ride it again next weekend at Oldenzaal.

C110

2011-04-15T04:08:00.000-07:00

My C110 also had some work done to it, and I even rode it to work for a few days.
The original front brake arm had a lot of play in it because of worn rubbers, so I temporarily replaced it with some balljoints and a piece of 8mm threaded bar, this really improved breaking because there is no more distortion in the system.
Now I want to look at replacing the bushings on the original brake arm with bearings, then I will have the same effect, but with original looks.

And I openend up the rebuilt C110 motor again to fit it with a kickstart shaft I found on ebay, it is now ready to be fitted.
Note the breatherbox, the lid is homemade, with thanks to Ralph for lending me his original unit.

newest pics

2011-04-15T04:02:00.000-07:00

The new "screw-ons" (imitation clip-ons) have been on my moped for a while, but I didn't take good pictures yet, so here they are.

Now only to decide what colour I want to have this bike painted, I'm thinking of Honda scarlet red, but suggestions are welcome.

ready for testruns

2011-04-15T03:41:00.001-07:00

The RSC90 is ready for testruns now, the tank is borrowed from one of my dad's CB72 racers, but it is fully mounted. I had looked at using a std. tank that I borrowed from Ralph but it turned out to be easier to use this tank instead, because I allready removed the original brackets from my frame.
So Ralph is getting back his tank afterall.

I plan on riding at Oldenzaal the 8th of May, a nice long track with many twists and turns.
I will look into mounting the fairing before then, but I might just run with a small oval on the front for my numbers.

line-up

2011-04-06T12:45:00.000-07:00

The weather was nice, all the bikes were at the workshop and I had a camera with me...just felt like a "kodak moment"

all my honda's lined up, and in the background you can spot the Beemer.

long time no blog

2011-04-04T13:19:00.000-07:00

It isn't like nothing has happened, but I've been busy at work and didn't really feel like doing much at the computer.
The S90 had some more testsessions, swapping exhausts with different bikes.
Conclusion: the camshaft has a timing for an open megaphone.
So the cam was swapped for another, still a hotcam compared to a standard S90 cam, but not the wildest one.

After the cam was swapped, we did another test, it started easier, and responded pretty well to the throttle, with the intended exhaust with muffler.
Also much quieter, what means power to the rear wheel instead of making noise.

first turnover

2011-03-13T14:06:00.000-07:00

Today, the S90 had its first turnover, with thanks to the gastank lent to me by Ralph.
It was strapped at the back, with an SS50 tankmount rubber, but atleast it fitted at the front, as the frame is wider then the SS50 tanks I have.

Of course it didn't start right away, I didn't have spark.
After checking just about everything, it turned out to be dirt and/or conservation between the points that needed some sandpaper instead of the normal filing with a nail file.
After that was done, It started reluctantly, telling me that it wants some work done to the carb to get it running properly. But it sounds potent, a little too potent for a sunday afternoon in a rural area, so we took it back inside again to continue with jetting another day, after I took some pictures.

Next to my moped it is just a small bike.

tough choice

2011-03-13T04:06:00.000-07:00

Yesterday (saturday) I had to work until 2, but after that I felt like taking a ride on the BMW. but when I came back to the workshop to change back to another bike to take home, I had a difficult decision to make... which one should I take home:

I decided on the SS50 (middle) and It will bring me to the workshop again today, so I will have the same "problem" today.

swapmeat today

2011-03-05T14:18:00.000-08:00

Today, my dad and I went to a swapmeat called "vehikel" and found some nice parts, mostly small things, like a couple of bolts I needed for one of my SS50's, a BMW R50 headlight holder and a length of rubber profile for the Oudshoorn BMW seat.
At one of the BMW stands, I found a footrest in a bin, one of maybe only 20 made for the Oudshoorn BMW's, my dad only had one with his bike, but what are the odds of finding a second one?
He probably won't use it as they are very low, but it is just nice to have the complete set.

And I bought a set of tyres for the C110. Front tyre mounted on a rim just to see what it would look like, as it is a cheap rimprotector until the bridgestone 2.00X18 is back in stock.
Yes I will change the wheelsize to 18" with 1.2 shouldered alloy rims and skinny tyres, not original, but looks damn good, I've seen it on a japanese bike.

rocker trouble....solved

2011-02-27T13:11:00.000-08:00

This weekend I was at my local honda shop, again... and picked up some original rockers and small parts in case mine couldn't be rescued anymore.
But after some grinding and machining, the old lightened ones are saved, let's just hope they don't break.
Compared to the originals you can clearly see the weightloss, about 5 grams per rocker.

And then of course I also had to lighten the rest of the parts for the real racing feeling. lightened the valves by about 2 grams and valve spring retainers also lost 2 grams each.

Installed in a nice clean head:

The cylinder it will go on, 45mm bigbore, I suspect it to be a modified CD125 piston in 4th oversize, I bought the kit as is.

Headgasket needed to be changed because of the bigger bore, so the inner diameter is a bit bigger then the one that was in the gasketkit, but also the thickness was increased to lower compression to about 10,3:1
With the bigbore kit, the original compression of 9,5:1 would have been raised to 11,5:1 when using an original headgasket, this is a bit much with modern 95 octane fuels at the pump.

This is the result of today, a finished engine, so far.
All bolts have been replced with original cross heads, and all parts I had are mounted. Still need some oilseals and a few bolts for the headcover to complete this, and would like an ignition with cover, but I could take that off my other engine for now.

The oil-line goes directly from the engine to the head, not through the carb, as I might mount a different style carb to this motor at some point.

rocker trouble

2011-02-23T11:53:00.000-08:00

I took the rockers out of their cover for the first time, as you can see from the picture, someone has done some work on them with a grinder, probably to lighten them.

But it doesn't look real professional, and when looking at the adjusternuts, you would really say it was a crappy job.
both nuts didn't fall flat to the rockers, but grind in the corner, exhaust being the worst:

So I will have some work to undo this, I will have to lighten the rockers some more, but in ways I am not so sure about, so I hope they will not break when I'm finished with them and doing 11.000RPM.

more valve covers

2011-02-20T14:36:00.000-08:00

Found these at my local honda shop this weekend:

To ad to my collection of valve covers:

If someone needs covers like the last ones in this picture, they still had a box full of them, on the bottom of that box I found these chromed covers and some strange red anodised alloy cap that I plan to modify with a small window, so I can see my lightened valve spring retainers rotating. Just for fun.

C110 engine build

2011-02-20T11:21:00.000-08:00

The gasket set is in from the UK, thanks to ebay, so the engine could be put together again, and that is what I've been doing this weekend.
As said before, the 5speed gearbox wouldn't fit, so the original 4 speed has gone back in, it was in great shape, so no work needed there, only some new bearings. The same applied for the crankshaft, new bearings and a cleaning to get rid of the old castrol racing oil.
As this engine was used for racing, there was no kickstart shaft, I didn't find a complete new unit (yet), so I've decided to keep the racing pedigree alive and block off the hole with a nice alloy plug.
The alloy clutchplate had some bad grooves in it, so I replced it with a new one I had laying around, together with new steel and lined plates, this should work fine again.
Also mounted the breather unit to the clutch cover, together with the blocked kickstarthole, this gives a nice racing-look.

After this I mounted the 45mm cylinder and piston, so I'm ready for some head-work.

To complete this motor I will need to find some more parts, because I'd rather not cannibalize the running C110 engine that is now under the bike. Enyone who can help me with a clutch adjuster cover, ignition and ignition cover? And if possible an intake manifold and carburetor?
Although I'm thinking of putting on a bigger carb, should be 1960's kei-hin, with a racing look, something like a CB160 powerjet carb, if I can find it.

And don't mind the allenbolts, they will be replaced with original crossheads, will be ordered together with oilseals and some other parts still needed.

Beemer out of the corner

2011-02-14T15:45:00.000-08:00

the weather is getting better, and sometimes I really feel like riding, but the beemer needs work, so "let's get to it" I thought.
I cut some material from the rear fender, looks a lot sportier then the original.

And hung the fairing on the bike, to get an idea of what it should look like.

Will need stiffer front fork springs before I can fit the fairing, or it will hit the front fender when I mount it where I want it to be.

breather

2011-02-14T15:30:00.000-08:00

The S90 has a nice breather with labirynth dipstick, but the rules say I also have to have a bottle to catch any oil coming out, if anything were to go wrong.
I couldn't decide what to do, it should look a bit retro, maybe an old oilcan, but what I found was too big. This is a small bike, it should have a small bottle that does not interfear too much with the lines of the bike.
When holding some bottle's upto the bike, this is what I came up with:

Generic plastic bottle hold by a honda inletrubber-clamp off a cb450, resting on the brakelightswitchmount (anyone for scrable?)

Also the electrics are finished,
might be running them inside the frame, but for now this works, I've seen less pretty solutions on original old RSC pictures.

It is a racebike, it should be functional, this can mean it will be a bit raw, but I like that on old racebikes.
I'd rather see a bike, fresh from the track with ducktape and lockwire repaires then an over-restored one.

This is how my bike looks now, just need to make a tank.... like it's nothing.
Then fit the seat and a fairing.
Or number plates, as it would be a shame to hide the mechanics.

electrics

2011-02-08T11:45:00.000-08:00

To get the 90 running, at least for a testride to see if the engine works, I need to do the electrics of the bike.
Not really much to do, but I want to do it right, so it will be easy to work on in the future, if I have to take out the engine, or remove the rev-counter.
As I will be running a battery-ignition system, I need an on/off switch. I was thinking of a toggle-switch, but I couldn't find one, but I did find an old SS50 ignitionswitch, so I decided to make a bracket for that, so it could be mounted somewhere in sight and accessible when sitting on the bike.
So the original S90 igniotionswitch-hole was not an option, I want to see if I have the ignition on when I am waiting on the startline for the flag to drop.
Once I pushed the CB72 for about 20 meters before I remembered the ignition.......

This is what I came up with for the RSC90:

The key will be secured with safety-wire so nobody steals it in the paddock, and also to prevent it from falling out, as this was a very old switch, the key can be taken out even when it is turned on...oops

The reason why I replaced it on my SS50.

90 swingarm

2011-02-06T01:11:00.000-08:00

With the CB50 racer I experienced an enormous change in handling when the swingarm was converted to needlebearings, so naturally this was also planned for the 90.
Honda uses rubber silentblocks in their swingarms which will flex when you turn into a corner.
These silentblocks have abnormal sizes when compared to standard bearings, this is why a bush was made to fit around the 24mm bearing and into the 25mm swingarm.

This will be pressed into he swingarm and blocked off using our "patented" maintenance free method.

90's of australia

2011-02-04T14:53:00.000-08:00

As seen before on my blog, Stew Ross has an S90 he is converting into an RSC. He sent me pictures regularly and we exchange ideas about our builds.
Here is one of the most recent pictures of his bike.

Keihin CR26 carb added and note the MT125R top crown plate with the racing brake and clutch levers.

Rencently I recieved some pictures from Mark Knowles, also from australia, and also building an S90 racebike. He has his engine all finished, bored and stroked to 124cc (54x54) with lightened cranck, clutch, rockers, valves, well almost everything actually.

I hope to see the progress as these bikes are being completed.

90 engine finished

2011-02-01T13:37:00.000-08:00

My 90 engine is finally finished.
Last week I recieved the titanium valve spring retainers for my 90 motor so it was time to mount them and finish the cylinderhead.
Back when I compared SS50 valvesprings with S90 springs, I must have made a mistake somewhere, as the inner diameter of the outer springs differs.
This meant that the springs had to be "helped" a little bit to fit the retainers, but that all worked out.

Fitted together with PM/rocky valve spring set to cope with the high lift camshaft of unknown origin. As original springs would bottom out at this high lift and wouldn't give enough pressure for a high revving engine with this cam.

Further modifications of my engine include:
Lightened valves and rockers.
High lift camshaft.
Ported head with matching intake manifold.
Kei-hin CR29 carb. (the real old model)
53mm piston kit in alloy cylinder.
No rotor on cranckshaft anymore.
Close ratio 4th gear

all combined to form this picture:

recent developments

2011-01-28T12:26:00.000-08:00

The C110 cases are blasted, cylinder and head are still to be done.

But I needed the cases clean so I could look if an SS50 5speed gearbox would fit in there. Someone once told me it would fit with a minor adjustment to the shift drum, but I think he never realy looked into it closely.
The 5th gear would interfere with the wall that seperates the gearbox from the ignition, not impossible, but a lot of work.

But it gets harder still, the total gearbox of an SS50 is wider by about 5mm....
this would mean major surgery to fit a 5speed gearbox.

This project is off the table (for now..), the C110 will get a normal 4speed cluster.

This just in:
My titanium valve spring retainers for the RSC90 arrived last week, so the C110 engine will go to the back of the workbench for a while, to build up the 90 motor completely, everything is ready, just needed these retainers to finish the head.
Now I can look at valve spring compression, if I need racing springs or if I can use original and so on.

C110 engine stripdown

2011-01-22T12:16:00.001-08:00

When I bought my C110, I had a choice of two engines I could get with it for spares, from what you will see next, I think I picked the right one.

I started taking apart the spare engine today, The plan was to give it a bigger piston, some tuning work and getting it nice and clean in the blasting cabinet and repainting the cast steel parts.

When I took of the head cover, the rockers looked a little funny to me, but I thought that might just be 1960's production.
when the valvecovers were taken off you could clearly see that someone had lightened the rockers, and had even ground down the adjuster screw and bolt on the inlet side.

And when I took of the head, I was surprised by a high domed piston:

This looked very high to me, I couldn't wait to compare them to the pistons I had back home.

By now it was clear that this wasn't a standard engine, someone had done some tuning, but for what purpose?.....
The kickstart hole was blocked off with a piece of cork or rubber, so I assumed the shaft was snapped, as this happens a lot to C110 engines.

But when I opened the engine up, there was no kickstart shaft...
This engine was used for racing!!!

My C110 came from the north of holland, where they used to do grasstrack racing, could this have been used in a 50cc class, as the high domed piston and lack of headgasket would indicate a very high compression.
Also, the oil residue was very thick and my dad recognised the smell as old racing oil.
Did this engine run on methanol?

I took the piston home.
At home I had two pistons, that I thought were C110 and CY110, but now I don't know anymore.
From left to right C110,CY110,super racing piston????
or C100,C110,CY110???
If you know, please tell me.
All pistons are 40mm and marked "ART" ,as you can see, they gradually get higher.

rear brake

2011-01-17T13:14:00.000-08:00

I finally decided how to attach the rear brake cable.
As the footpegs are made for a brakecable and the original S90 brakeplate is meant for a brakerod, there was a problem.
I didn't want to weld anything to the brakeplate, but I couldn't decide on what it should be, untill last weekend, when I made this bracket.
I know similar brackets exist from aftermarket suppliers, and yamaha used something like this on their 125 production racer back in the days.

It is bolted with the brakestay and has a lip that falls against the edge of the brakeplate, very simple but effective.

CR110 replica forks

2011-01-05T13:27:00.000-08:00

I recieved 2 sets of CR110 front-fork-spring-support-rings (anyone for scrabble?) that I bought on ebay. One set will be for the RSC90 but the other is for an actually abandonned project. A Honda CR110 replica.
It was the plan to build frames and really change mine and my dad's CB50 racers into CR110 replicas, but the 50cc class has become too fast with modern 2stroke tuning, so I am abandonning the class altogether and also the CR110 project.
All the parts I allready had will be used on other bikes probably, or maybe sold.
The front forks were allready made for this project, it only needed these rings, so when I got the chance, I bought them.
It supports the spring where it rests against the lower yoke.

I think this fork will go into my SS50 motorcycle, combined with a front fender like the one made for the RSC90 and the same type of 160mm front drum laced to a WM00(1.20) alloy rim.

Will need to make some clip-ons to mount the original CR110 levers onto....

RSC front fender, part 4

2011-01-05T13:18:00.000-08:00

Last weekend I went on with the front fender for the S90 racer, I didn't really feel like it, but in the end I was glad I did the work.

mounted on the bike:

The weight really surprised me, and it still functions as a stabiliser because of the supports underneath the fender, just like original.

On to the next long project that has been on a rest for a while, the model for the gastank....

brakepedal

2011-01-04T14:44:00.000-08:00

My brakepedal was still smooth on top and I wanted it to have teeth on the flat surface, like a C(Y)B72 pedal. I never made something like this before, but I think it turned out pretty nice. Milled with a 20degree cutter, set at an angle.
In hindsight I should have made bigger teeth, but I can do that when this has worn away from use.

12 Volts

2011-01-03T14:29:00.000-08:00

The oudshoorn gets some real electrics, no fuss with a vulnerable old 6volt system, but 12 Volts out of a /6 Beemer.

And it still fits under the original front cover.

a little history

2011-01-03T14:22:00.001-08:00

I found this picture on the web, on this Belgian blog This is the Oudshoorn BMW a long time ago.
Before I was born? as I don't remember it like this, never seen black valvecovers or those dellorto carbs.

The caravan in the background I do remember, sadly the wood rotted away, but we still have the chassis which is now a trailer for my dad's sidecar.

RSC front fender, part 3

2010-12-28T12:44:00.000-08:00

Some more progress on the front fender, I didn't feel like it for a long time, so I did a lot of other small stuff but now it is really comming together.

I pressfitted the rods to the fender stays using 2 pieces of steel with half of a round hole cut out of both of them. The rod is now stuck in the stay and will be hold in place by some glue* when all is done.
(special glue also used for putting lining onto brakeshoes)
I bent the stays so they meet up with the fender, that is how it now holds the fender over the tire.

A view of the bike with the fender, for the bigger picture, I like it.

Next step will be to make some reinforcements to go under the fender and riveting it all together. I allready made a mold for the rivet heads by pressing a ballbearing into a piece of aluminium.

pedals part deux

2010-12-28T12:28:00.000-08:00

part three is still to come, my pedals aren't finished yet, but they are mounted and functional, when I have a rear brake cable made.

brake pedal still needs some "teeth" so I won't slip off.

Shift lever and linkage, with a hole drilled thru the pedal, like some original RSC/RC/CR levers had.

Connecting rod had to be bent to match up to the engine, so only threaded at one side for adjusting.

some more progress on the Oudshoorn

2010-12-28T12:16:00.000-08:00

My dad did a lot more small jobs on his BMW and I helped a little.
I had some tickle style headlamp brackets at home, that were supporting a CB72 headlight on my desk (my kind of paperweight) I fitted them to the ceriani/van bockel forks with an original BMW headlight my dad still had. It has clearly been on a caferacer before, as there are some extra holes and switches and there was only a tacho mounted, no speedo.

Also mounted the levers, they are reproductions of the old tommaselli levers, they fit well with the original tommaselli throttle that I allready found in the bottom of a drawer.

And for when it will not be ridden with a sidecar, a kickstand is fitted. Not the original as the bracket on the frame was ground down, this was made using Honda C50 kickstands and the end is off a Honda brakepedal. Mounted to a 10mm steel plate which sits between the frame and engine instead of original bushings.

first modifications for the C110

2010-12-19T13:44:00.000-08:00

I've done the first modifications on the C110, I don't plan on drastically changing the bike, just some different but if possible original parts.
I had a NOS C110 taillight that I bought for my SS50 motorcycle, but now I think this is a more fitting place to mount it.
I think it goes better with the round backside of the seat then the taillight that was on here.

Just need the correct screws to mount the glass, as honda used abnormal threads in the early days. This needs M3x0.6 while normal M3 has 0.5 pitch.
I didn't paint the taillight because I'm thinking of changing the color to red anyway.
For now this light is on so I can drill the holes in my licenceplate in the correct spot. It still has to be made, but the paperwork has allready arrived.
Date of admission to public roads is set at 1968, taken from the swiss paperwork, so I'm allowed to get an old blue licenceplate for the bike.
(modern bikes have to have ugly yellow plates in Holland)
This also means I had it approved as a small motorcycle, not a moped, so it's legal to bolt on some "go-faster" bits.

My new bike

2010-12-05T02:53:00.000-08:00

Yesterday my dad and I went to pick up a new bike.
This one has been on my wishlist for a while, and when I saw this one for sale on the internet, it looked perfect for me, complete with all the right parts.
It was a 180km ride to get it, and we were lucky that on the way there all the roads were clear, but the way home took a bit longer. The view from the passengerseat:

It is a C110 with Swiss paperwork, and because in Switserland you are not allowed to have a passenger, it had an original racing seat. (as seen on ebay for many $$$)
It is unmolested, allmost all original parts with original bolts, so a good place to start a restoration.

I'm not quite sure what I want to do to it, keep it mostly as it is, or change it to more of a CY110 with racing parts, like this bike found on a japanese blog called oldsportsrider
And for tuning purposes I've got an extra engine with the bike, so I can keep it running while building a faster engine.

I must admit, I goes a bit far to buy a bike to use some parts you allready had, but I will be mounting the original breather set on this bike that was in my closet for a long time.

Only need to make the lid for the labyrinth as I don't have that, but a friend has one that I can probably borrow to copy it.

pedals

2010-12-05T02:39:00.000-08:00

The last week I've been working on my brake and shift pedals for the RSC90. I have footpegs that are original CYB72 as also seen in RSC90 pictures, but I don't have the pedals that belong to it, and as they are very rare, I don't think I will ever find them.
So I decided to make my own, in the same way I made them for my CB50 and SS50.
I will be making them out of alloy, original would be chromed steel, but I don't want the hassle of chroming.
For now, this is how my brakepedal turned out:

I made it narrower where it mounts to the peg-brackets so it will be easier to put the bike on the paddockstand. The cable mount is different because original CB72 cables are hard to find and/or expensive.
And I want to make a grooved pattern in the pedal itself, but I don't know how I want it to look yet. After that, there will be some more smoothing and rounding off edges to make it look like a sandcast pedal.

This was made by welding some pieces of scrap aluminium plate together and then a lot of sanding and filing.
As you can see here, what is the beginning of my shiftpedal:

SS50 engine troubles

2010-11-23T14:29:00.000-08:00

Found the problem for the slipping clutch, it was weak springs, luckaly the local Honda shop sells extra strength clutch springs for a C50 clutch that will also fit the C110 unit. You only need to buy 2 sets as a C50 has only 4 springs.
When compressed to 12mm these gave 9kg's of pressure, compared to the 5kg's I had from the stoch C110 springs.
Also something was found for the gearbox problem, it turns out the old C65 casings have a higher hump inside from the footrest mounting holes. This caused my shifting arm to hit against it and not being able to give the full movement to the shiftdrum.
The piece marked in black marker was cut away and now it shifts like a dream.

RSC front fender, part 2

2010-11-23T14:16:00.000-08:00

I've made a die to press the ends of the front fender stays.
It is milled from a piece of solid steel and made specifically for 8mm (alloy) tube to be pressed flat like Honda used to do, with a rounded edge and pressed to one side.
The first test:

You can see some irregularities and a nick from the end of the die, so I made some changes by hand, I was happy by the third test:

And the stays as they should be put together:

I want to put it all together in the weekend as I want to take my time for this. I don't want to rush it in the hour after work that I spend in the workshop.

RSC front fender

2010-11-19T12:37:00.000-08:00

As the ss50 engine was built up again, I spent some time on my RSC project.
An aluminium front fender has been lieing on my front tyre for some while now, waiting for brackets to be made.
So I started the process. Found a piece of strong 2mm aluminium and cut out the right shape for a fender stay. It has been modelled after a C110 front fender stay although that has a thinner pressed plate example.

I chose 2mm plate for its strength, because I want it to also function as a fork stabiliser.
Something I experienced with my SS50 on the road with plastic or steel fenders, is that I do want a strong connection between the legs.
I will eventually round the edges of the stay to immitate a thinwall pressed plate stay.
The stays will be riveted to the fender and the 8mm tube will be welded to the stay after it is clamped in place by folding the tabs on the stay around the tube. Just like original fenders.
And to give you an idea of what it will look like:

I will also add a plate underneath the fender that will be riveted together with the stays, to add strength to the fender where it functions as a fork stabiliser. Something also seen in original (steel) fenders, mostly causing them to rot out from underneath.

the oldschool engine runs

2010-11-19T12:27:00.000-08:00

And it accelerates a bit quicker then with an original clutch.
I rode it home from the workshop today, hoping I could take it for a ride tomorrow, what is probably the last dry day of this year.
But....shifting is still not the way it should be, so I will have to open it up again and sadly the C110 clutch is also slipping like crazy. Tomorrow morning I will check if I did something wrong with the adjusters, but I am afraid that it is the plates or the springs.

valve spring retainers

2010-11-14T03:17:00.000-08:00

The old-school SS50 engine is back together again, and it has run, but I need to make a real testride to feel if everything is allright.
But when checking the head, I found something that didn't work.
I had made triangular valve spring retainers by grinding off parts of the originals, but this resulted in one point of the retainer getting cought on the end of the valve spring, stopping it from rotating over each other.
The solution: making a 6-pointed retainer.

from left to right:
original, old adapted retainer, new adapted retainer

Method: bolt the retainer to a piece of perforated sheet metal with round holes, then spraypaint, this will mark what you need to cut away.
My scales aren't exact enough, but you take off about 2-3 grams, this matters at 12.000RPM.

My new tank

2010-11-10T13:55:00.000-08:00

My new tank came in a few days ago, thanks very much to Matt Hummel
Trying it on my bike, to see if it clears the master cilinder, as the toaster tank I am currently using didn't and had to be slightly altered on the bottom to fit.
But this tank clears everything perfectly, probably made for the dual disc setup.
Insides are perfect, outside does have some rust as a previous owner started blasting it, but never finished.
I will have it painted black with white pinstripes, luckaly there is enough of the original stripes left to have them copied.

progress on the Oudshoorn

2010-11-10T13:37:00.000-08:00

there is some more progress on the Oudshoorn BMW.
My dad is busy fitting the cilinders, heads and pistons so it will al work together, not to easy considdering everything comes from different models.
- 700LS heads and pistons (car)
- /5 cilinders adapted to fit an R50 case that has been modified for long studs that run all the way up to the rockers.
- R60/2 cranck
- .......

old school altered front brake plate, only it should be in the original leading link front end, there will be an original front brake plate to go in these van Bockel (ceriani) forks.

more new parts on the oldschool engine

2010-11-08T14:51:00.000-08:00

New crankcase for the "old school engine"
well, not exactly new, it comes from a used C65 motor. I wanted these because of the mounts underneath the cilinder for a guard plate. At some point an oilcooler will be mounted on here.
After glassbead blasting:

Nice that there is no engine number, the old engine must have had the cases swapped at some point.
BUT.....these are 1960's cases, this means problems like I've encountered with the S90 motor, but didn't expect on this.
different locations for the guide pins, should both be be on the top tappets in this picture, but they are not, so I can use only one that corresponds with my cilinder.

A hole, my piston for the camchaintensioner will not block this and won't be able to build up pressure, will have to find/make a longer piston.

The piston I had in the other cases, with the long spring. And the short spring that was with the C65 cases, this tells me I need a longer piston.

new clutch for the ss50 engine

2010-11-08T14:24:00.000-08:00

I have been collecting parts for my "old school tuning" ss50 engine, to replace the original clutch with one from a C110.
The C110 has an aluminium center that weighs a lot less then the original ss50 clutch. Although my engine had a 2plate clutch from a chinese copy. even more weight then the original 1plate, but it was the only complete clutch I had laying around at the time.
C110 clutch:

Only it doesn't fit onto an SS50 crankshaft without modification, so I had my dad grind the inner diameter to fit the SS50 crank, then the splines fit.

On all sides it needed some work, the primairy sprocket needed some work to fit onto the gearbox main shaft. Some spacers needed to fit the whole clutch onto the crank, and a bearing holder had to be fabricated to let oil thru, as the c110 doesn't have that.

To give an idea about the weight loss
2 plate:

C110 clutch:

Now to finish the engine so I can hear the difference in revving, I'm looking forward to starting this up and hearing the difference.

A nice bonus is the difference in primairy reduction.
SS50 originally has 16:69.
my 2plate system had a 17:67 reduction.
And the C110 has 15:70. this means the gearbox will make less revs, letting it shift easier.

90 valves

2010-11-08T14:14:00.000-08:00

The valves for the 90 have been done.
Thinned down the shaft for the length it sticks into the port with full lift on the cam.
This means more space for fuel to get thru and a reduction in weight, this will help in the higher revs.
Also they have been ground into the seats to see where the contact is, and the edges sticking out have been removed and rounded to let fuel pass by the valve easier.

Also removed weight from the side of the valve that is in the combustion chamber, the loss in compression is minnimal, but you will notice the reduction in weight.

Sharp edges removed from the combution chamber.
Now only to wait for my titanium valve spring retainers to come in and then the engine can be completed.

we're back

2010-10-24T13:58:00.000-07:00

I've had a slight computer problem, but I'm back online now.

In the meantime I've recieved some nice packages in the post.
12" sidecar wheel I just couldn't let it pass me by.
Seen here next to the 16"front wheel of my dad's sidecar racer

You don't have much opportunities to get these, and it might look great on my dad's Oudshoorn BMW.

Also bought some nice carbs on ebay for my own BMW, because I'd like to determine the position of the throttle slide instead of it being "automatic" like in the original carbs.
These are 36mm BING off an R75/5.
But I will have to alter my footrests first or my foot will get jammed between the shifter pedal and the lower part of the float bowl.
This will be a winter project.

Today I checked the oil levels of the driveshaft, gearbox and final drive, because I had some leaks. Might be a seal put in backwards by a previous owner, this will be checked in winter, for now the levels are correct again.
But when working on the back, the broken rear fender began to really bother me.
The mudflap covered the damage, but I wanted to get rid of the flap because it made my bike look like an old geesers machine.
So I took the grinder and reworked the rear end.

Looking a lot more sporty now. I want to do more to it, but for that I would need to take out the fender, not something I want to do when I need to take the bike home again, or rather, it had to take me home again.

screw-ons mounted

2010-10-02T12:10:00.000-07:00

Today I mounted the new screw-ons.
here you can see a new one mounted and an old one still on the right (of the picture)

A lot of difference in the height and the angle, on my way home I allready found it a lot more comfortable.

Original throttle controls:

Drivers view:

Because I have a twin leading front brake off a CB125k1-5 my front brake cable has an 8mm ferrule, where an SS50 only has a 7mm ferrule. This was never a problem because I used CB-type levers and switches, but now my brakecable wouln't fit into SS50 type switches so I had to machine something to match an 8mm cable to a 7mm hole.

By the way, my old set of screw-ons is now for sale.

screw-ons

2010-09-29T12:56:00.000-07:00

On most of my bikes I have clip-on handlebars, but on my SS50z I wanted to maintain the original headlamp stays, so I made fake clip-ons for it, I call them "screw-ons" because they are mounted with the top fork bolt.
I had two sets of these before, that I found on ebay, but they have been sold, the set that is now on my SS50z was homemade, to look lower, but I took a guess about the angle of the bars and that turned out to be too much downwards.

Now I've been making a set to replace them.
All parts together before welding:

The slots have been milled out at a 5 degree angle, this is a standard measurement for clip-ons (5, 10 or 15 degrees)
I didn't want it to be straight, that would look to simple and to much like zündapp clip-ons.

I asked my dad to weld the bars with copper, less warping and I might want to have these chromed in the future, I don't know if that would be possible if these were welded with silver.
For now, painted black (frame colour) just like the 60's racebikes.
Slots have been milled out for the original SS50 throttle controls and for the wires to go thru the bars, even if it is only for 5cm.

Note the levers with little ball ends.

Underside, throttle cable comes out thru an original rubber grommet.

I hope to mount them on my bike tomorrow after work, if there is no overtime.

Rockers

2010-09-19T13:51:00.000-07:00

Lightened rockers for the 90, about 10% lighter then original.
It does take some time to do this, but it is nice old school tuning.

And a nice points cover I scored on Ebay, originally off an ATC110.

ribbed for extra cooling, I think I'll need it as I do not want to install a "modern" oilcooler.

New camshaft

2010-08-04T13:53:00.001-07:00

Today in the mail I recieved a new hot camshaft for the 90 that I had won on ebay. Didn't have much info when I bought it about timing and lift, So I was hoping it would be different from the hotcam I allready had. And I was lucky.
From left ro right: original S90 cam, hotcam #1, hotcam #2

More lift and duration, looking forward to building the 90 engine again, it has been on a bit of a standstill.
The racers needed work and I am making new handlebars for my moped, time is scrace during racing season.

unknown piston

2010-08-04T13:02:00.000-07:00

My dad is building an 85cc race engine based on an XR75 (post 1976), it is for a friend who will race it at a moped racing club.
This guy brought over a lot of parts to build with, including a big bore piston.
I like this piston, for the 50mm bore that is was originally built for, this one is a 50,75mm bore, 3rd oversize.
This has a 13mm piston pin, just like xr75.
But this piston didn't have any original box, or any markings, so I don't know what it is.

Can you help me identify this piston????

50mm standard bore
13mm piston pin
And very distinctive valve indentations.
But I can't even be sure it is honda, it might be something else.
If you have any idea what this is, please send me an email.

How to make a cable

2010-07-20T12:55:00.000-07:00

For the RSC90 I've made all the cables by altering original or aftermarket honda grey cables, like I've done for my other bikes. A while ago, someone asked me to write it all down and make somewhat of a manual for altering cables.
Well here is the method I use, from what I know, I think this is the best way to do it.
But, in this modern world of prosecuting people, I take no responsibility for the cables you alter, this is just a guideline.

I start with a Honda or aftermarket cable, I like grey, but this can also be done for black cables of course.
This example is of a front brake cable for a twin leading Honda front brake, normally I would shorten this from the top, but in this example I used a cable that was already cut at the bottom and added the original adjusters to it, that have been taken off old cables before they were thrown away.

You start with cutting the inner cable at the nipple that you want to replace.
Then you take out the inner cable, and cut the outer cable to length.
I use an angle grinder for all cutting, this leaves clean straight cuts, do not use wirecutters for the outer cable, the uneven end could screw itself into the inner cable, blocking the function. You need a flat end off the outer cable:

Now you replace the ferrules at the ends that have been cut off, in my case this is the big adjuster that goes onto the brakeplate. Sometimes it is possible to take off the old ones from the end that is cut off, but is is much easier to buy new ones. I get my supplies from the cable-shop.
Now you want to put everything onto the cable, it wouldn't be the first time someone has it all soldered only to find out he forgot the adjuster that has no slot to slide it onto the cable afterwards.

Now you unraffle the inner cable (the steel nipple on this cable is homemade to fit the twin leading hub, nipples for the top to fit into the levers are normally available) the nipple is also fitted, as it can be difficult to get it on after the cable has been rewinded.

The outer wires are oppositely wound to the inner wires.
Take the inner wires and unwind these also, this will have a straight wire in the middle, cut this down about 1cm.

After this, rewind the inner cables, and then the outer cables, when done correctly, this will leave you with a normal looking cable, but with a small hole on the end.
Sadly my camera couldn't really get this clear.

Now you take a piece of steel wire (not stainless) about 2mm diameter, and make a wedge out of it, I do this by rotating it against an anglegrinder with a sanding disc.

Cut it off, long enough so you can still handle it.
Then it is inserted into the hole on the end of the inner cable so that it is spread outwards and the nipple is pushed onto this.
You should be able to pull on the nipple without pulling it off the cable, even before the wedge is soldered into place. This way, the strength comes from the cable being wedged into the nipple instead of the solder, this will just keep the wedge from falling out.

The tools for the job:

Use the flux on the parts you want to solder, heat the nipple and cable and then apply the solder (tin/lead) from the bottom where the wedge sits. (use silver for stainless cables)

Stop when you see the solder creeping thru the cable at the top of the nipple.
At this point, let it cool gently, afterwards you can grind away the excess parts of the wedge and/or cable. Now you can mount your cable.

This method will work on clutch and throttle cables also, with throttle cables it isn't always necessary to take out the middle strand, as the strands are thinner and more flexible.

I wish you good luck altering your cables, and if you have questions, don't hesitate to ask.

stator replacement

2010-07-14T14:06:00.000-07:00

The replacement for the 90 stator is ready, it has a mark to check the points and a bolt screwed in from the back, that holds the oil pump gear in place.

Too bad the aluminium turned out to be really soft, when I tightened the three bolts, the aluminium expanded, actually causing it to get pushed outwards against the casing.....
For now I'll let it be, and get on with building the rest of the engine, but I think this part will be replaced by something of better quality.

front brake

2010-07-14T13:59:00.000-07:00

The CB72 is ready again for the event in Lelystad next weekend. I had some trouble with the front brake, Honda 200mm drums are too light, when really used, they grow so much from the heat that the spokes become loose. From one of my dad's other CB72 racers came a front wheel with Suzuki T500 front drum, now fitted with a honda brakeplate. These hubs have a thicker lining and can withstand the abuse of racing with modern tyres.

New silencer from Honda

2010-07-14T13:29:00.000-07:00

I was just looking around the CMS website, when I came across this new model silencer from Honda.

I think its cool, I just don't have the "model" this plugs into.
they also have a red version.

RSC rotor

2010-07-11T11:40:00.000-07:00

On the 90 I will not be using the original rotor and stator assembly, to save weight on the cranck, and in total, I will be running a battery ignition that will be recharged before every event.
But to check the ignition timing and valves, I need something to determine "Top" and "Fire".
I bought a ct90 rotor from Loef that I modified.

All the weight has been taken off, leaving just the center with the cone and slot for the woodruff key. Onto this I bolted an alloy disc (bolts will be replaced by original honda cross-head bolts)

And then copied the markings from the original CS90 rotor onto the alloy disc.

This rotor will be permanently mounted to the cranck, as I don't want the hassle of putting it on every time I need to check something.
Next step will be an alloy ring to replace the stator, it will have the mark for timing and something to keep the oil-pump shaft in place.

Racing at Purmerend

2010-07-11T02:46:00.000-07:00

Last week we had an event in Purmerend at a closed off industrial area. I raced my 50 and my dad's CB72 to compete in 2 classes. This was the third event I rode the 250 to see if I would like the "big" bike.
Action shots are thanks to Lea langezaal, the club photographer, see more of her pictures on the CRT website
The number 2 bike is an Aermacchi.

Unfortunately in the last heat, the motor shot out of gear, or so it seemed, I was quick with the clutch, had a look if I could see anything wrong, but nothing to see. I tried to release the clutch gently, but that didn't feel right, so I quit.

Back home, we took out the engine, my dad has three of these bikes, and raced them with friends. Back then, the bolt that alligns the shift fork with the shift drum had broken before, so that was believed to be the problem. But when we opened the clutch cover, the real problem became all to clear: broken primairy chain.

This is a "normal" thing to happen to a CB72, especially when raced, but usually the chain cracks the cluch cover making it clear what happend, in my case it didn't even leave a scratch on the inside.
Fortunately my dad had a new stronger chain set ready to fit to this engine, just didn't get round to fitting it yet.

progress on the 90

2010-07-05T12:24:00.000-07:00

I've done some work on my RSC90 project as well, assembled all the clutch parts and fitted the cover, with breather unit.

Also fitted the bigbore piston and cilinder, although it has to come off again because I can't remember if I put the knock pin in. I hope I did because the pistonrings were a pain to get in, when the cilinder was bored out, the sloping edge has disappeared.

Chain tensioner has been put in after this picture was made, but I have to figure out a way to keep the oil-pump sprocket in place as I don't want to use the stator which normally keeps it from moving side to side.

pictures from down under

2010-07-05T12:14:00.000-07:00

I recieved some more pictures from Stew's RSC90 project.

He found an original honda stand for only 10 dollars at a swap meat. Think it's from an MT125 or RS125 2stroke racer, but I'm not sure, my stands were homemade from pictures.
Note the details, MT125R top yoke, lightened rear sprocket and everything else.

Long stroke experiment

2010-06-24T11:29:00.000-07:00

Sadly the experiment didn't turn out to have a big effect.
After a lot of fine tuning it might give a little bit more then the current short stroke motor, but not enough to make a real impact in the 2stroke dominated 50cc class. So I'm thinking of quitting the 50cc altogether to focus on my RSC90 and maybe a CB72 that I've been trying for the last two events.

For now the 50cc has been converted back into a short stroke, with some minor adjustments to the head, valves and camtiming to get power at higher revs.
Next weekend is the Honda-day with a dyno, lets see what the little 50 has to give.

Long stroke experiment

2010-06-18T13:51:00.000-07:00

A new experiment to get some more torque out of the 50cc engine, as it is originally a short stroke, at 35,6mm with a 42mm bore.
Now a test using an XR75 cranck wich has a 41,4mm stroke, just like an SS50.

Cylinder is sleeved to get to a 39mm bore, combined with a GB2 piston, originally of an engine with horizontal cylinder.

Tomorrow its first run....

R90/6 café transformation

2010-06-18T13:30:00.000-07:00

The transformation into a caferacer has begun.
Clip-on handlebars, found in the spareparts bin of my dad's racing history, originally 35mm but adapted for the 36mm BMW forks.
Under the black paint, it turned out I had a chromed top fork plate in good condition.

Real magura's, no modern stuff.

And the Laverda SFC tophalf fairing I want to put on. I started with a different style tophalf, but that didn't have enough height to fit the headlight.

5speed first gear

2010-06-05T14:30:00.000-07:00

Since I've been riding with the SS50 motorcycle it has had an original unmodified 5speed engine. Now only the ports and valves have been lightly tuned, but wat has been buggin me from the start; the short first gear compared to the closeness of the rest of the gears.
My other engines have 4speed gearboxes, that have a problem with a big step between third and fourth, but that is not as annoying as the 5speed first gear.
Also this is dangerous, as the 5speed gearboxes are known to break when shifting from second to first while riding, or they break when not properly kickstarted, as the gears are to narrow and the kick-gear only engages for a few millimeters.
(Three out of four of my 5speed gearboxes had a broken first gear)

To avoid breaking and to get a closer gearbox, I decided that the "oldschool-tuning-engine" although newly built and never run, was going to be opened up to change out the first gear for a modified first from a 4speed gearbox.
Thanx to my dad for the modifications of the shaft and sprocket.

Top: modified 4speed first gear (13:35)
bottom: original, broken, 5speed first gear (12:36)

And some other tricks that have been applied to this engine:
Old copperplated rockers, lightened.

Thin homemade cylinderbase gasket.

2-plate clutch to prevent slipping, please forgive me for it is from a chinese engine.

But to make up for the chinese clutch, an S65 clutchcover with homemade finned adjustment cover. Note that there is no indentation under the adjustment cover as in the later types, this means 0,73L of oil instead of 0,7L.
On the front is the oil line for the carb-heating that is blocked of now, I want to use this for an oil-cooler in the future. And mounted onto the filler opening, a nice breather unit like the one on my RSC90.

And a lightened cranckshaft, turned on the lathe to remove weight, but only where it could be removed over the full 360 degrees so I didn't have to balance the cranck again. And onto that a new high compression piston, not the old one from the SS50 5speed models, but from some new dax, it has the same compression ratio, but it weighs 20% less.

engine overhaul

2010-05-31T14:00:00.000-07:00

The 5speed SS50 engine that was under the motorcycle was leaking some oil from the cylinder base and behind the generator cover, so it needed to be taken apart, even though it has only done about 500km.
The problem at the cylinder base turned out to be a cylinder that wasn't flat, so it was turned on the lathe to get a flat surface for the gasket to sit against.
I thought it would also have a leaky cranckshaft oil-seal, but it was dry in the center of the generator. Next guess was the O-ring around the stator plate, when I took it off the plate, it was so dried out, that it broke instead of stretching.
So hardened it doesn't even lose its shape when broken:

when the head was off, I took some pictures of it, next to my "old-school tuned engine" this has an older type head with even bigger fins:

and more importantly, nicer ports:

Both are cylinderheads from the 5speed models, with extra and bigger fins then the 3 and 4speed models, but even then there are differences.

The other head has since been flowed to look more like the "old-school" one

breakdown

2010-05-26T12:15:00.000-07:00

Tuesday I took the moped to work, but when driving home, it began to vibrate at high revs and it made some funny noises. 5KM later I was at the workshop, had a quick look if the flywheel nut might have come loose, but it didn't, so I thought it should be a clutch problem. After all these years of abuse, I finaly managed to break the engine.

Today I started disassembly by taking of the exhaust to have a look at the clutch, but to my surprise, it turned out to be as simple as a broken motormount bolt.

I had a new bolt, put it in, put the exhaust back on, started the bike, and the vibrations were gone, engine still in working order, dispite years of abuse.
This motor has almost no compression, you can hear the piston ratteling in the cylinderwall, it never gets new oil, at best the old stuff out of a race-engine, it gets overrevved, overheated with burnouts..... but I still can't get it to really break. Real Honda quality, no chinese parts.

Jet problems

2010-05-26T11:37:00.000-07:00

The SS50 motorcycle engine is now pretty much run in, but the carb settings are a litlle of. So I thought I would try a different main jet but to my surprise the keihin SS50A carb is so old that it doesn't have the standardized jets still used today. Now available are jets with 4mm and 5mm treads, as far as I know M4 and M5, but mine has a coarser thread M5x1 ???
In any case it has the same threads as the jets used in the CB72 PW22hov carbs I have, the powerjet type.

some measurements:
5mm threads

6mm head

8mm long

and a view of the coarse threads

If anyone knows where to get these old jets, please let me know, I need something like a 75 or 78

BMW test

2010-05-22T13:13:00.000-07:00

I've been riding my R90/6 for a little while now, and I am starting to get used to it, but at first I thought it was a real heavy beast that didn't want to go round corners. Making it into a caferacer would then only make that worse, with narrow clip-on bars and such.

When I was young (about 15 years ago?) my dad built a BMW caferacer together with Jan Hoogstraten who stil ownes the bike. We asked him if we could borrow it for me to experience what a BMW caferacer would feel like. Here it is next to my R90/6

I've only ridden it for a few kilometers now, but it isn't disappointing, I want to ride it some more, to get a good feel of the bike, but I think I'll keep my R90/6 to turn it into the JBT-interceptor styled caferacer I had planned.

The M10s on the back is the name of the bike, being compiled of the enginetype; R90s and my dad's name; Martien ("tien" means "10" in dutch)
Note the single sided paralever swingarm from a later type.

slipperclutch

2010-05-22T12:27:00.000-07:00

The SS50 motorcycle had some problems with the clutch slipping through at high speeds when asking full power. As this weekend I want to ride it in a night time honda-run, I wanted this fixed, so I opened up the engine, even though it has not even run more than 500km yet.

I found that the clutchsprings I had put in, where probably new as there was still yellow paint on them, but they were weak compared to the new springs I had with partnumber: 22401-036-000.
when measured at compression to 15mm the yellow springs had 5kg while the 036-springs had 8kg.
So new springs were mounted with new plates, as you don't know if they might have been warped from slipping, although I saw no blue spots on them.
First testrun it seems okay, lets see if it will hold.

engine building

2010-05-07T14:05:00.000-07:00

The building of the racing engine has really begun.

I've fitted the altered 4speed gearbox with 3-4 made a little closer.
Fitted the best cranck I have with new bearings, oil-pump cleaned and fitted with new gaskets.

Gear shift drum turned out to be a bit different from the one that was in this engine originally.
That one had a circular plate on it as I know off the SS50 engines, but it couldn't be fitted to this gear shift drum, as it is a bit longer and then the clover shaped plate on the end wouln't fall onto its guidepin. So no extra plate here, should be no problem.

Next was the shift shaft, both shafts I had were bent, I bought a new one, but that didn't fit. The shaft was 0.5mm thicker where it shoulf fit into the right cranckcase and it had no bushing for the spring to fit over.

Now the shaft is turned down on the lathe, and a loose bush is made to fit over it, just as in the newer engines. so it fits in my old cases without altering them.

Shopping at the local Honda store

2010-05-07T13:38:00.000-07:00

This evening I went shopping, the CB100 needed a new throttle slide for the handlebars, as the old one was pretty well worn. And then I allways think of other things I might need.
Like I want to put blinkers on my ss50 motorcycle, but don't have a switch for it. I have CB type switches on the bike, because of the normal throttle in combination with the clip-on bars. When browsing thru the CB50 parts at the shop I found an english style CB50 switch in new condition.

Although I don't really want to take it appart to use only the top half, I bought it anyway, maybe someone I know would be happy with it to use on their german CB50 as they don't have high/low switches.
Also in the CB50 bin, this nice SS50Zk1? switch with the separate on/off switch and (p-L-H) on top instead of (off-L-H), I know these were used on general export SS50Zk1's with the racing style seat. I just couldn't leave it, with this I can also have a parking light on one of my SS50's. Not because I need it, but just because it is possible.

First event of the year

2010-05-02T10:57:00.000-07:00

Last friday was the first event of this year, in Nieuw Vennep there was a section of industrial area where they created a track. In the morning we had some rain in training, but in the afternoon for the first heat the sun began to shine, with the second heat the track had almost completely dried up. I had to get used to the CB50 again, as this was the first ride since last season, but I've got the hang of it again. Some pictures with thanks to Lea Langezaal.

Me (75) chasing Cor on his sachs (57)

more pictures of this event found on the CRT website

computer crash

2010-05-01T12:22:00.000-07:00

Sadly I had a slight computer crash lately, so that was the reason there have been no updates. I have lost some of my files and some links to interesting pages. Now I am starting to get things up and running again, and updates are on the way, as the bikes haven't been sitting still. But if anyone has nice links, please send them so I can get my favorites filled up again.

SS50 twins

2010-04-20T11:20:00.000-07:00

This weekend I went to a honda 4stroke meeting to run in the ss50 motorcycle, did about 250km and it performed better and better. It is now back at the workshop so I can do some maintenance, but when I switched it for my moped again, I made some pictures of the two of them together. The smallest one is the motorcycle.

BMW stripdown

2010-04-17T13:31:00.000-07:00

Today is the start of my one week vacation, time to take apart the BMW and check everything before I start riding.

At the end of the day, even the front forks were taken out.

Went to the local BMW shop to get some small parts, where we also found some used fork rubbers, will make the bike a bit more sporty, and ready for a top-fairing that I would like to put on in the future.

Big sump my dad had laying around, will add to the caferacer looks.

A big difference to what I am used to, NOS SS50 alloy cylinder next to an R90 cylinder, and the R90 has two of them.

BMW

2010-04-11T11:25:00.000-07:00

I have been looking for a larger motorcycle for a while now, for daily use, but a classic with caferacer potential, usefull around town but also on highways. As I grew up between BMW's and Honda's I was thinking about bikes as the CB750k, BMW R75 or larger.
My dad has been riding BMW's for most of his life, he advised me to get a BMW because of maintance, parts, resale value and usefulness.
The boxer engine always appealed to me, as it is different from everything else on the road. I remembered a cool BMW caferacer from the Joe-bar comics, the JBT-interceptor and decided I wanted to build something like that. To start with I was looking for a complete running bike with some key features;
-750cc+
-double disc brake with early calipers
-wire wheels
And not too expensive as my budget is limited and keeping in mind the changes into a caferacer, like a tophalf fairing, narrow fenders, sporty seat and maybe a 4LS front brake if I couldn't find anything with twin discs.

Last week I found a nice bike on the internet with potential, not completely original, but a real classic, an R90/6 from 1974. It had the alloy blinkers, twin discs, early calipers and had recently had new tyres and battery.
Today we went to have a look at it, and as we (read: my dad) were satisfied with the state of the bike and performance on the testride, I bought it.

At home we found the front axle wasn't clamped in the forklegs, and some other small points of attention, so before I will start riding, we will give it a full service to be safe. And maybe the first modifications, as I allready have a nice cafe-style front fender. But I now have my first real motorcycle.

glass blasting

2010-04-10T10:20:00.000-07:00

Today's work; degreasing and glassbeadblasting the casings, to prevent glass from getting in the engine later, all the threaded holes are plugged with old bolts.
Before:

After:

Nice details from under the dirt.

Progress at the end of the day.

taking apart the 90 engine

2010-04-05T13:17:00.000-07:00

Over the last few days I've been taking apart the S90 engine Ralph gave to me.

Piston is dirty and cilinder looks a bit shabby, but I won't be using those for this engine, will be cleaned and preserved as spare parts.

All taken apart, no real disturbing finds, just an old engine that has regular wear. I think the center casings had never before been taken apart as they were stuck together as if they were glued.

Only weird thing was a broken gear shift drum, the missing piece has not been found yet, a previous owner probably took it out.

mkII Golf lowrider

2010-04-03T13:31:00.000-07:00

My daily transport for the longer trips is a 4wheeler, Not a Honda TRX, but a car and not even a Honda.
It was a present from my dad when I got my driving license about 2.5 years ago, he had this car in his backyard for a while before I got it.
It is a 1986 mkII Golf C, the most basic form there is, luckaly it is the 1.6L and not the 1.3L, so it has a little bit of power in it.
Since I had it, I have changed the wheels from 13" steel rims to 15" alloy BBS (original VW) and I found a rev-counter someday that has been mounted on top of the dashboard, as the Golf C doesn't have one as standard, it has a clock instead. Further changes are not significant, but were needed for the yearly technical inspections (APK). This years check was coming up so I had to change the rear shocks as that was a point of attention last year, and also because it was so completely rotten on the right rear that in winter water would get in and freeze, giving me absolutely no suspension.
Instead of just changing the rear shocks, I chose to get a full adjustable lowering kit, step one to making a cool looking Golf. Although I do like my Honda's more so I don't have a lot of plans for the Golf as I can only spend my money once.

Some picture's of today's work, with many thanks to C. de Vos, who is a racing-friend who ownes a garage. He did most of the work installing the lowering kit.
BEFORE:

Just about 22cm to the spoiler.

First try, the rear looks nice, but the front is a little low, we do have a lot of speedbumps here in Holland.

AFTER:

Just under 14cm to the spoiler.

Lowered almost 9cm.
Didn't think it would turn out that much, but I like it.
The rear is lowered almost 4cm, but that was compared to my old rotten shocks.
Handles like a go-kart now, lots of fun at the roundabouts, but most of the comfort has gone.