Sorry i had to be a bit of a smart-ass. If no one has given you a link a little later ill get one when im actually on my computer. Bit of a pain to do on my phone.
Cwr kit is a 88 or 89mm piston i believe they bore out a stock jug and put their own sleeve in but you need the cases bored too to fit it. Probably the best youll get is the 366 je piston
i believe its an 89mm piston in the cycle works kit. makes 401cc. i've thought about building one of these for the spare bottom end i've got laying around. i can bore the cases myself and do the sleeve so would save myself quite a bit of $. should make for a nice high rev motor.