broken exhaust stud

I broke an exhaust stud on my 70cc kit, about to do a tap & die, and switch to a 1/4-20 bolt. any tips on how to do this right .

Re: broken exhaust stud

Did the stud break inside? I had one break and I was able to remove it with vise grips.

Re: broken exhaust stud

why does a 1/4 20 sound really, really small? and 20 tpi seems coarse.. what are the original threads?

I'd drill it out large enough so the tap removes all the old stud's threads .. And drill out the cylinder's bolt hole passage to fit the new, larger stud, if required.

Re: broken exhaust stud

I don't know about the pitch, but the stud size sounds right on, not small at all. Puchs and several other bikes use studs to hold the exhaust on. The nut uses a 10mm socket or wrench to remove it. Most 10mm nuts are 6mm diameter for the bolt or stud. 1/4inch is about 6.35mm, larger than the stock stud on many bikes.

really really small-no

too little over stock-maybe.


damn.. i screwed up .. didnt see the "exhaust" stud part .. misread this thread as a cylinder stud problem.

But i'd still go oversized, big enough to clean away the old threads whatever that takes, especially if it's an aluminum cylinder.

Might be a good idea to do both sides.. If the pipe was fit correctly and nuts were torqued correctly and the stock stud's threads tore out, the studs may be undersized for the load.

Re: broken exhaust stud

Brian Mikami /

I stripped the threads on my studs, but was able to vise grip off. Don't know if it's because I have the BiTurbo and bore kit, but it's real tight in there, a skirted nut would'nt fit and the socket barely fit. Going much bigger that stock may be difficult, check for clearance first. I've heard of using brass nuts so the nut strips before the stud. I don't know how you stripped out the cylinder (if you did that) or broke the stud...good luck.

Re: broken exhaust stud

John Joedicke /

So go to 1/4 - 28 if you don't like 20

Re: broken exhaust stud

Yeah I Concur go with 1/4 28 threads you will remove less metal and have greater gripping strength. more threads equal more bearing surface for the two materials.And also use brass nuts they won't rust to the threads and potetially lead to another brocken stud.Jim.

Re: broken exhaust stud

This is a easy trick, just get a nut that is about the same size and weld the stud then the nut and remove it works everytime for me and if your worried about heat get sum cold wet rags. good luck

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