CB50 caferacer

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

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

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??

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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