Re: dax f80 with 36t or 41t sprocket?
With a stock, unmodified motor with the kit supplied exhaust pipe/muffler even with a 36T sprocket you're going to be pushing it to attain an actual 35mph. Some of the claims you see here of 35, 40 and higher are in some cases, a little overstated. If you're set on hitting 35 or higher you're going to have to go down in sprocket size, possibly to a 32T. Now you'll have good top end speed but your hill climbing ability will be almost nothing. The 41T is a good compromise and will keep you down in the safe bicycle speed range. I always stress that we're building motorized bicycles, not motorcycles. A sustained 35mph on a bicycle is fast. Probably too fast for safety.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"