Sunday, October 2, 2011

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.

- 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.