KDX Top End

Regarding the comment above on the smallend bearing, would the outside diameter match the conrod, and inside the wristpin so theoretically a px one would do if a standard crank was used.- Ive got a yz125 topend Im trying to graft on to smallframe casings,the smallend is the current hurdle I'm facing as the vespa wristpin is 15mm on the smallframe.( feel free to edit or delete)

Thanks. I've fixed up the error. I'm running a KDX piston on a standard(ish) Vespa crank, with a standard Vespa smallend bearing.

It should not be too hard to locate a smallend bearing of a sensible size. It was pure luck that the Vespa one fitted, however they come in all sizes and thicknesses. Check out the Comp-PinsClipsBearings.pdf as a starter. A bearing shop after that.

hello mR. internet scooter...i was wondering....of u wanna do a top end conversoin, what are the points to take note...is it the displacement???and how does the powervalves work on vespa??

finding something that suits the current crank is the main issue (just to start with).

We were testing the power valve last night, we just had it set in either position and have decided to leave it in the high rpm power. At this point we think that is fine, the gearbox is sensitive, so it doesn't make sense to strain it taking off. On a drag bike, though you'd want to get power in both ranges.