Front Studs keep Beaking!!!!!!

M

Micky

New Member
So I am new to this, but fell in love write away, anyway. I've put less then 20 miles on my bike, and twice I have broken 1 stud the first time, and 2 studs the second time (after a decent ride, at no more then 20 miles an hr, because I'm breaking the motor in) After the first time, I had to drill out the stud. Then I replaced it with a grade 8 bolt instead of a threaded stud. Then both bolts I replaced them with broke off as well( I'm about to try to get those out write now ) Oh, and by the way! I bought ( what I thought was the write stuff ) the rubber mounted engine mounts. Now I'm thinking it's got to much give or something. " Please Let Me Know, Somebody, If you have any Idea's " I will be greatly Appreciated. P.S. I Know this as been posted probably, but I apologize about asking again if that's the case.....

Micky:-||
 
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Re: Front Studs keep Beaking!!!!!! WTF

Get rid of the rubber. It doesn't work and will result in the problem you're having. The engine MUST be mounted solid to the frame. No rubber, no resilient material whatsoever between the engine and the bike frame.

Contrary to myth and products sold by vendors, you can not eliminate the vibrations produced by the engine but the rubber will transmit those forces directly to the fasteners and cause them to fail.

Tom
 
Re: Front Studs keep Beaking!!!!!! WTF

Thank you, is this a common problem though? Will the grade 8 studs even make a difference?
 
Re: Front Studs keep Beaking!!!!!! WTF

Micky said:
Thank you, is this a common problem though? Will the grade 8 studs even make a difference?
Click to expand...
The problem is inevitable if the engine is allowed to move in its mounts. Rubber will do that.

The hardness of the stud material isn't really a factor. What is important is the condition of the threads in the case. If they are worn or damaged the studs, or bolts won't hold well and will loosen. Damaged or bad threads can be repaired with a thread repair kit (Heli-Coil). Do not try to fix them with JB WEld or any epoxy.

Many of us replace the studs with Allen head capscrews. Typically they will come in a metric 8.8 grade hardness. Plenty hard enough for mounting purposes especially when you realize that you're threading into relatively soft aluminum.

Tom
 
Regarding the hardness scales and hardware store fastners,
Metric grade 8.8 is basically the same as SAE grade 5.
Do not use SAE grade 8 or higher for the engine's mounting as they are so brittle that you run the risk of them snapping before bending under stress. A bent engine mount stud or bolt is better than a snapped one. At least it will still be there trying to hold the parts together and you can unscrew it from the engine case instead of drilling and using an easy-out.
 
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