Hi. I have converted an Aprilia RS125 with the addition of a GM 3kw motor and compatible 80a controller at 72v. Unfortunately, the power is woefully inadequate. The sprocket ratio is 1:5 (11 tooth front and 55 tooth rear). I am unable to fit a smaller front sprocket due to the 20mm output shaft of the motor or larger toothed rear sprocket as any it would require structural changes to the swinging arm and the frame. The chain is a 428 type. I have gone for a minimal look with a bespoke seat unit. I now think that the bike needs at least a 10kw motor. I had a quick look at hub motors but I want to keep the aesthetic look of the bike. Does the forum know of any UK companies / individual that deal with part exchange motors/controllers as I haven’t an exhaustible budget? The next job is fitting out the 12v system. I don’t know whether a QS hub motor is the best way to go?
Regards Simon (Lincoln UK)
