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1970 CL100 Cafe Project - Bore Information?

10419 Views 31 Replies 10 Participants Last post by  monkey
Yo! Sorry if this is a subject that's been covered already. I'm new to the forum and couldn't seem to find anything. So! I bought a 1970 CL100 back in July from the second owner, who bought it back in 1973. He used it sparingly, but maintained it well until about five years ago,. It has sat since then. I stripped the bike to a motor and a frame, and all seems straight forward thus far except for the motor. Given the scooter-esque displacement, I'd like to add a little more get up and go, while simultaneously getting rid of any compression problems that may or may not be present. So, hey! Let's just bore it, right? BUT... I have no idea what the best compromise between sustained reliability and performance may be... I've heard of people boring the cylinder to fit a 750 sleeve and piston, and that it's extremely reliable, the only difference being that the 750 piston requires a 15mm wrist pin rather than the 14mm in the 100. That can be reamed, correct?

But is that even the best option? What would be the displacement, horsepower, and performance gains on this? Would anyone happen to have firsthand experience with doing such a modification on this bike? Any and all performance/reliability tips would also be greatly appreciated.
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Ding.........another bike gets its wings.

Powroll has kits for the 100 but you need some machining. You can use a 125 piston but I think the pins are slightly different.

I heard of folks doing the 750 piston work but what a machining and tuning nightmare. Stroking it out, compression issues.......just a lot of poop...for what.......18 hp.

But Wits never get what you want out of this 100. Since your probably going to cut up the frame make a straight 125 by sourcing a motor or maybe a 175.

You have a good history being the 3rd owner of this classic honda..... but it would be a shame to cut it up to a cafe only to get a r top speed of 75mph....maybe.
There is no way in hell of reaming a CL100 rod to oversize said:
Danger, is[/I] my business."
100 and 125 heads are the same size with the exception of bigger combustion area on the 125....interchangable. 125 piston will fit with 125 machining.......besides displacement. 125 rod, Powroll rod, or a Powroll stroker rod, etc. A 125 rod with a 750 piston will yield 150......I believe but not sure.

A lot of work for maybe 18 hp with exhaust
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