Exhaust pipe threads stripped

[Stoneman]

Yeah I can think of something. Check that the nut that fits this "one size larger" stud can actually fit on next to the exhaust pipe. There is not much room for the M6 nut so I am very sceptical that an M8 nut will fit and be able to turn.

An Allan head mate not a nut

If you use a stud, yes. The nut likly won’t work, haven’t tried.

 

[FurryOnTheInside]

An Allan head mate not a nut

If you use a stud, yes. The nut likly won’t work, haven’t tried.

Using an M8 Allen head bolt you're limited to 19Nm torque at the very most because of the crappy cast aluminium. The OP's exhaust was shaking loose before, and okay that may have been due to not having a muffler support bracket but the fact remains that an M6 stud can be loctited in place and then double nutted which is far better and more secure than any M8 bolt. A properly done double nut is far more secure because the torque limit is that of the steel stud not the cast aluminium. I posted a detailed and hopefully newb proof explanation of the double nutting procedure in a similar thread just a few minutes ago for anyone who is interested.

 

[Stoneman]

I agree, they should be studs.

 

[Spare_Parts]

Had similar happen. Tapped to m7 without drilling and it fit fine.

 

[GreenMantis]

Drilling and tapping is probably your best, if not only option to repair this. However, this doesn't address the underlying issue that caused this in the first place, so you would only be doomed to failure again. I think what you need to do is brace the muffler properly. I'm guessing you probably didn't do it in the first place, and if you did, you didn't do it well enough. You need a bracket that supports the muffler itself, and ties it to the frame, so that it's entire weight isn't hanging by only those two bolts that hold the pipe to the head. Mine came with straps for that, if you don't have those, plumbers strap would be my go to, it's cheap and versatile, I always have a roll of that stuff around, since it comes in very handy sometimes. You just need to support the weight of the muffler from the muffler end.
Just imagine yourself grabbing the end of the muffler, and shaking it as hard as you can, if that seems like it would break it off the head, that's because it probably would. But if you secure the other end of it, then that is an entirely different matter. Without support, the thing is acting like a big lever, applying a bunch of leverage to pulling those bolts out.

 

[GreenMantis]

Using an M8 Allen head bolt you're limited to 19Nm torque at the very most because of the crappy cast aluminium. The OP's exhaust was shaking loose before, and okay that may have been due to not having a muffler support bracket but the fact remains that an M6 stud can be loctited in place and then double nutted which is far better and more secure than any M8 bolt. A properly done double nut is far more secure because the torque limit is that of the steel stud not the cast aluminium. I posted a detailed and hopefully newb proof explanation of the double nutting procedure in a similar thread just a few minutes ago for anyone who is interested.

I completely agree, I did the same thing. I double nutted 6mm stainless steel studs. The bag of studs was a great investment, worth every penny.

 

[kyakguy]

So my exhaust pipe kept coming loose and i decided to buy new screws and washers to keep it on tight. I unscrewed it and noticed the threads on the engine were chipped/ stripped from the exhaust shaking around and ruining the threads. The engine runs great ive only had it a month or so she goes up to 50kph easy and it gets me to work and back no problems until this. Ive tried riding without the exhaust it is LOUD. any ideas how i can make it quieter or somehow get the exhaust back on.
Please helpp thanks. I uploaded pics

I tapped hole to 1/4 " w/lock nuts used red locktight for studs and a 2" hose clamp to fasten muffler to frame. good luck

 

[Lukesky36]

double nut your exhausts studs it helps alot