On paper the standard C110 gearbox is pretty close, nicer then any standard OHC gearbox, but while riding I felt the step from 3rd to 4th was a bit tall, so for the racebike I was wondering if anything could be done about that easily.
I have a lot of ratio's on paper of different gearboxes, so looking at OHC models, which have the same distance shaft to shaft and a similar 4speed system I found another gearbox with a shorter 4th gear that might just work in a C110. I had a look through my leftovers of various gearboxes and came up with an SL70 4th gear what would be my best bet. An SS50 4th gear could also be used, but then I would have to remove more material from the 3rd gear for it to work, and I didn't want to take off too much.
Seen here the original C110 gearbox with the parts to modify taken off, and on the bottem the new 4th gear, which is too wide to fit in a C110.
To make the SL70 primary 4th gear work, I had to take off a little bit from the 3rd gear cogs so they would slot into 4th. So it went on the lathe with the anglegrinder attachment.
After that, it's time to narrow the SL70 primairy 4th gear, again, grinding it on the lathe. Same was done the the secundairy SL70 gear, and after that a lot of cleanup to get the lathe free of all the grinding dust, including taking the chuck apart and cleaning the insides.
C110 gearbox, with close ratio 4th gear upgrade kit (in the middle) :
And a quick pic mounted in the engine.
Now I really want to finish the engine and get the rolling chassis done so far that I can feel what a difference this 4th gear makes. Theoretically it should make the step from 3rd to 4th about 40% smaller.
The start is there, first part of the brackets with clamps to hold the CR110 pegs like they are mounted originally. Some self made pegs made to fit. Shift lever will bolt directly to the motor and face backwards when ready. Now to make the bottom part of the brackets and a brake cable holder. But I allready like the looks.
wanted a 20mm powerjet carb for a long time, and now I've got one, NOS from ebay. I thought this would be the perfect period correct "racing" carb for the C110. I have some 22mm's off a CB72, but they are just a bit too big. Made a flange to mount the carb to the frame in original position, and the manifold that came with the carb was turned down to fit a S65 rubber that fits onto the original C110 manifold.
Today's work, well a bit of it. The front brake anchor made from aircraft grade aluminium with a custom bolt to hold it to the brakeplate with M8 12mm castle nut anybody have an extra front brake arm, early cast steel type?
The big rim, spokes and tires changout trick is just about done. The wheels off my C110 streetbike have been laced up to 17" rims again, alloy morad, just untill I can find original DID rims. And the hubs for the C110 racer came in from belgium and after some beadblasting and pollishing, have been laced up to the old 18" rims that came out of the other bike.
Now it's really starting to look like something, with wheels and tires in the correct dimensions. Still need a front brake arm, some bearings and then its on to make a fender and so on.
just started putting some parts on Found some parts to put together a set of rear shocks with NOS top covers and used chrome ones that are still okay, with stiffer springs on the inside. Hub was supplied by a friend, brakeplate and sprocket carrier I still had.
disregard the OHC engine casings, they are just weight to keep it from flipping backwards and chipping the paint.
Bottom yoke, lower legs and chain guard freshly painted the Black parts are for my dad's BMW sidecar.
and a set of clip-ons made in CR110/RSC style now also painted.
Tomorrow when the paint is dry, I can really start getting it together.
Anyone who could help me get a set of rear tank cushions?
As of today, I have a red C110. Thanks dad for painting it. As seen in the picture it was painted outside, so there is a fly or two in there, but then this is an old-school racebike, this is the way they did it back then. Maybe someday if I were to restore it, it could be painted again, but for now it is more the case that this one is saved from the scrapheap.
As I am gathering spares to restore my C110, I was realizing that a lot of stuff will be left over at the end of the restoration. Tank, engine, forks....
So when I heard that a friend should have an extra frame laying around, I contacted him to make a trade. And so started this project. It will be a C110 race bike with mostly period correct original racing parts For now a quick mockup with the CR110 forks and the wheels taken out of the SS50 race-project which will be cancelled for now (leftovers for sale)
