Hello, I am new to this forum and am very interested in building a motorized bike. I have a Ryobi bc30 engine that is practically new and would like to use it on a GEBE kit. This looks like a fairly simple way to get started. GEBE sells two sizes based on the clutch size. I have done a lot of research but can't find out the clutch size for the ryobi engine 52mm or 76mm and I am not sure how to measure this. It seems that larger engines use the 76mm and I would guess the ryobi to be the 52. Also there are 4 different gears that GEBE sells. I am 200 lbs, the bike is a 26" mountain bike and I live in very hilly, mountainous terrain and will drive mostly dirt roads. Advice on which GEBE gear would be best. Thanks for any and all help on this.