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Old 12-23-2009, 03:30 PM
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FileStyle FileStyle is offline
Motorized Bicycle Elite Member
Join Date: May 2008
Location: Decatur,IL
Posts: 724
Default Re: Seat tube motor bolts keep breaking?!

I concur to all who have posted! I also have a ride with oversized tubing (downtube,seat stay) and instead of rubber I use leather! (from a belt) the reason you are breaking bolts in my opinion is 1) chain is too tight, 2)rear sprocket is not mounted true center or 3) the motor is not quite straight in the frame! I too had that problem one time and it turned out the reason was because I had moved the motor in the frame and the sprocket was not dead center and I had tightened the chain when the rear sprocket was on the short side, so when I took off for a ride there was a terrible vibration, unlike before and before I made it back home, the left rear bolt had sheared! these were socket head bolts from my local bolt Co. not the factory stock studs. after I relieved the chain of the tension and readjusted my rear sprocket I have no problems.
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