Calling all 125 owners (sprocket sizes).

czowner · 11-14-2009, 10:04 AM

The motor in my Hongdou has finally given up the ghost, so as a quick fix I've been down the breakers and bought a 125 motor. Using the same 17/42 sprocket combination as the 223cc motor it struggles up to 55mph, using the 15 tooth which came with the motor it screams up to 60mph and cruises at 40mph. What's everyone else using? It would seem like I need a 17/46 which splits the difference. I've gone for the larger rear as smaller than 17 teeth on the front and the chain rubs on the top of the swinging arm.

Jonathan.

Reveeen · 11-14-2009, 11:59 AM

Try these tools on for size:

http://www.dropbears.com/u/utilities/gearing.htm

11-14-2009, 10:04 AM	#1
czowner Join Date: Sep 2006 Location: North East England Posts: 313	Calling all 125 owners (sprocket sizes). The motor in my Hongdou has finally given up the ghost, so as a quick fix I've been down the breakers and bought a 125 motor. Using the same 17/42 sprocket combination as the 223cc motor it struggles up to 55mph, using the 15 tooth which came with the motor it screams up to 60mph and cruises at 40mph. What's everyone else using? It would seem like I need a 17/46 which splits the difference. I've gone for the larger rear as smaller than 17 teeth on the front and the chain rubs on the top of the swinging arm. Jonathan.
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11-14-2009, 11:59 AM	#2
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	Try these tools on for size: http://www.dropbears.com/u/utilities/gearing.htm
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