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

the clutch

....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......

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

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

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

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

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

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

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

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.