Hello
I plan to do some modifications to the wife's YBR 125cc, engine and frame, to do a little scrambler off road. My problem is just the engine, I know it's possible to put a piston and sleeve to give a 163 cc. French firm Scorpa sells such a trial bike, but the mod is done by an another mechanical firm that never replies to me. I found the kit in Japan, but the price is japanese of course !!!
If you have somes ideas of chinese parts that can do the job, I'll be very happy for your help, I know the piston must be 63mm in diameter....
I just buy by internet a trial bike Bultaco 350 Sherpa, from a guy of my small village in south of France, and I want my wife able to follow me in our Crimean mountains...