We'd tried to variate an a35 once, but derbi style with a GY6 clutch and vario in place of the transmission gears.
It actually fit up pretty well, the belt motion didnt line up well enough though, and the reduction ratios are off. it was more of a fun concept idea cuz we had the parts laying around and got bored. but one of the biggest issues it had that you might also encounter is lubrication of the trans side seal which is setup to be lubed by the transmission. without some sort of oiling vent or somethin it could be a problem. maybe not though.