P200 into px125

My mate has a dead px125 and a running p200 engine he wants to swop the p200 internals into his px125 casings(so he can keep his electric start,autolube and original engine numbers)anyone know if this is possible and if so are there any unforseen difficultys?

is the 125 actually dead or is it just the usual performance we expect from a 125? its hard to tell.ive never actually met a british scooterist that has a px125 with a non p2 motor in it.you live and learn.how dead is the dead 125?.its rare for them to be totallly un-resurectable,theyre just too simple

Your mate can swap all the internals over from the P2 until you get as far as the clutch,(although this will fit with the P2 CLUTCH COVER) AND, and its a huge AND, you cannot fit the crank, barrel and piston. So you end up with exactly what you started with but higher gearing. A very long way to go about it. Just fit the P2 engine and register the bike with the new engine number, then tune it! Or if you are after the same performance of a P2, fit a 166/177 kit. have fun!