Nice idea using those pocket bike rims..I have given it some thought before..using a rear Coleman 8" rim same..the stock sprocket is 50 tooth 420 chain so may want to change unless you want 5 to 1 ratio using 10 tooth clutch..you can get 16" or 18" tires for those 8" rims..which true tire diameter is usually a little smaller..that cross member behind motor may have to be bent or removed to clear..motor is close too..kinda gave up on idea weighing needed mods