Noral speed range?

Larry Trotter

Active Member
Nov 26, 2017
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I have a 66CC (supposedly) on a 700C bicycle. 10 tooth front sprocket and a 41 tooth rear. Today I downloaded a speedometer app and the bike will make 28mph level ground and 90 degree temp. I am about 155lbs. Is this about the performance I should be expecting from this setup? I would like it to run a little smoother at about 5 to10mph but cannot pull the 10 tooth drive gear no matter what I try, even a 3 arm puller. I ahve a 9 tooth to try. How much larger rear sprocket would I need? Larry
 

Nashville Kat

Well-Known Member
Apr 20, 2009
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Jacksonville, Florida
I think you have your gearing reversed in your mind- if you're after more speed- you need larger gears on the front motor end and smaller sprockets on the back. 36 teeth rear sprocks are quite popular- at your low weight you might get away with 32 if you aren't riding a lot of long hills. The smaller rear sprock also gives better frame clearance and so you can more likely lose the tensioner and match the chains, which may require half links- the pedal side is easier to vary.

I might use today an aftermarket spring tensioner, but never tried one here yet.

This gives a "longer" gear in inches- higher top speed- less revs-noise and vibrations for the same speed- and that usually is a China Girl motor PLUS- at slightly less low speed torque pulling- you might have to pedal just a bit more to pop the clutch and take off, or bog down on large hills
 
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Larry Trotter

Active Member
Nov 26, 2017
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I would be fine with it topping out at 22 to 25 but I need it to be able to run a little slower while the engine is running smoother. I can run it at about 5 to 10 but the engine is just barely at above slow idle and is rough at that speed. I live in an old person park in Arizona, so it would be nice to be able to go slow and quiet. Larry
 

crassius

Well-Known Member
Sep 30, 2012
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drive sprocket comes off with the puller in the kit - 2-strokes don't like slow speeds, so I usually slip clutch a bit to get rolling thru a parking lot, pull clutch and coast a bit, then repeat
 
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