Thursday, October 23, 2014

CB72 racer

Had one of my dad's CB72 racers out to testfit a CR93 fairing that I have for sale, someone wanted to know how it would fit a CB72.

Fits it quite nicely I would think.
And then we rearranged some of the workshop, what meant that another CB72 came out of a dark corner, making me want to start this project.

Not with original tank and (replica) CYB seat as seen here, but with something more like a CR72 tank, period correct and with a lot of home made castings and other replica parts, and even some originals. As I have collected some CYB72 stuff over the years.
I have, or can build many of the small parts, the tank will pretty much be the only part I really don't have any idea of where to find or how to built yet.

Thursday, October 16, 2014

S90 trial

another great project from a friend, who is building an S90 trial bike.
And I will so lucky that I get to work on some little things for this bike also.

Wednesday, October 8, 2014

end of season checks for the C110

the racing season is over now, so time to check the bikes and store them for winter.
At the last event the C110 started shifting a bit less smooth, so I wanted to open up the motor to see if I could find anything.

couldn't really find anything with the gearbox except for normal wear, well, not even normal as the bike is about 50 years old and all I could find was a small mark on a shift fork. Made some clearance there and that was it.

Then wanted to clean the clutch, as it acts somewhat as a centrifugal filter and found this:

oops, although I've seen them worse in pictures.

luckily I had a spare engine by now that still had a good clutch center, so this is going back together as it worked fine up till now with the extra preload washers with heavy duty springs.

Just one modification I wanted to do to the gearbox, I replaced the standard stopper arm with an S90 part, these have a little roller on the end, that might just prevent the selector to stick between gears. I've had this happen a couple of times so hopefully this helps, or the fact that I now swapped the old style shift arm for a more modern type, eliminating about 2cm of play in my pedal.

Monday, September 29, 2014

the last event this season

Last weekend was already the last event for this year, Giessen, for me the first time here and I like the track a lot. So hopefully we can ride here again next year.

We took a lot of bikes with us, left to right:
-the C110 racer for the oldtimer class.
-CB50 racebike we overhauled for someone to do a couple of test laps in the oldtimer class, luckaly it behaved all good so I could jump on my C110 after 2 laps en do the rest of training with that.
-My dad's old CB50 racer that we had a friend ride in the 50 class.
-My own CB50 that didn't run very well in this experimental phase, took a little getting used to again to rev between 12.500 and 14.500.
-and last but not least, my RSC90, reliable and quick, might just open up the engine this winter to see why it is as quick as this, because I can't really believe how it's doing so well.

Friday, September 26, 2014

picture day

Not bikes this time, but parts.
homemade cast aluminium parts.

Honda CR750 pedals

Honda RS125 / RS250 foot pegs

Honda CR110 pedals and pegs

Honda MT125R top yoke

Honda replica brake plate for 160mm drum

Honda CR110 / CR93 perches

(in machining all evidence of mirror mounts will be removed, better then plugging one up or welding it shut)

Thursday, September 18, 2014

JRP covers for sale, part two.

the top engine covers / breather kits are also ready now
for sale as a set with the points cover or separate.


only 10 to 12 breather sets will be made

Wednesday, September 17, 2014

JRP covers for sale

I've now got 5 JRP points covers for 6v monkeybikes machined and ready, but I don't have that much engins myself, so some are for sale, if anybody is interested, give me an email.

I'm also working on the top cylinder head covers / breatherkit, but they are not ready yet. Will be available soon, and also as a set with the points cover.

Friday, September 12, 2014

2 more days of aluminium casting

Last week, I planned two days of casting and managed to create some more nice parts

some Honda MT125R top yokes, CR750 pedals and shift arms, CR110 pedals and pegs, also useful for other Honda racers like RC162, RC181, CR450, CR72 replicas and so on.

Another 160mm TLS front brake plate and a bunch of JRP engine covers for monkey engines, most of which are already reserved for friends.
Guess I'll have to do some more casting...

Wednesday, August 27, 2014

after Den Helder

Den Helder went pretty well, the RSC90 ran like a top but once back in the workshop I discovered the cilinder base gasket is leaking some oil, so sadly I will have to open up the engine.

picture from the CRT website
Note the 4LS front brake is back in there and this time it worked.

The longer brake lever on the C110 front hub didn't do what I hoped it would, still pretty much no front brakes and they became really hot, so I decided on making some cooling holes in the hub.

Angled so the rotation of the wheel will create a vacuum to draw out the hot air.

Maybe I want to create some sort of small air scoop on the brake plate just above the lever, but I'll have to put the wheel back in the bike to see if that wouldn't look horrible, and this is now how the bike stands:

Rear brake was terrible also, so swapped some brakeshoes and having everything skimmed to fit again.

On the bench also a bigger front hub, replica CR110 built to match the forks in the past, but I want to try and keep the original C110 hub, it looks nicer.

Thursday, August 21, 2014


Okay, last weekend was another event, and again I forgot to take pictures, the day is pretty full when riding 3 classes and doing repairs in between.

The RSC90 had a brake problem in training, so I swapped the 4LS wheel for the spare 2LS with homebuilt brakeplate, which performed perfectly.

(picture from the CRT website)

The C110 did really well, only the brakes leave a little to be desired, might be they are too small, or that I can't get enough force into them, so I swapped the brake lever for a longer one to see if that will help for next weekend.

And then there was the CB50, took a little getting used to, as it revs much higher then the other bikes, and now found it annoying that the tachometer wasn't accurate anymore since I had fallen some time ago where the tach had some damage afterwards.
So finally I decided on making another tachometer that would be accurate even in those high revs. and the old one from the 50 went onto a CB72 where it is no problem if the accuracy goes down above 13.000rpm.

Step one, take a standard Honda tachometer and open it up.
Step two, make a little bracket that stops the needle at 3, or whatever you make your custom face start at.

Step three, replace the face, and paint up all the outside bits to the colour of your choosing. In my case black, like the original CR110 tachometers where my face is modelled after.

Step four, put the tachometer back together again, seen here still resting in the cilinder liner that has been modified to become a tach-pressing-tool to crimp the original ring closed again.

and in between, check if it still works okay, these things are delicate, I'm glad this one went well, and also like the completely white needle and black surrounds, the first ones I did were different, but I like this better. Less fuss, more pure racing use.