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Old 12-10-2010, 01:10 PM
Nashville Kat's Avatar
Nashville Kat Nashville Kat is offline
Motorized Bicycle Elite Member
Join Date: Apr 2009
Location: Jacksonville, Florida
Posts: 1,403
Default Re: Need help in changing out the mounting studs.

Here's what I've done to two builds- and I personally would prefer it to any adapter even if it were an option-

Grind or file down the mount casting on the motor, roundish, until it fits over the larger frame tube-the grinding of the enlarged engine mount just starts getting over the motor stud drillings- which are 1/8" more narrow than the frame down tube- that means you have 1/16" inch on each side to get past the frame- Don't worry, this works! The motor steel is actually alloy and files away fairly easy- maybe 20 minutes of time with a hand file- faster with drill grinder.

Then get longer studs- the first time I found longer bolts at an auto store and cut the heads off to have studs that were a half inch longer than the original- But the second build I got smart-

order two BACK engine mount studs- they are longer to go through the additional frame coupler- and the perfect length for this front mount method. About 3 dollars each- try Bikeberry.

After grinding the motor wider, put in the longer studs- then, using the flat of a large crescent wrench, VERY CAREFULLY bend the studs, about 1/4" at the bottom to clear the frame, being careful not to break them.

Place the motor on the frame and press it down into place- the studs will scratch the frame slightly to clear- I touch up the scratch with paint and clearcoat to prevent rust

the motor case where the threads are doesn't reach the midpoint of the frame tube, so clearance isn't as bad as you might think.

Once the motor is snug on the frame, take the crescent wrench and very gently bend the studs back at the bottom to fit the bottom steel clamp. It helps sometimes to pound the clamp a little flatter with a hammer if necessary, to separate the holes further.

anyway, the studs then actually slightly wrap around the frame- I use pipe insulator type material at the motor and clamp for vibration- and it's really a secure mount-

the studs CAN'T back out because they wrap around the frame and can't turn otherwise. It seems a little starnge bending the studs but it works great. The studs have to be about a half inch longer at least though.

Last edited by Nashville Kat; 12-10-2010 at 01:12 PM.
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