Exhaust pipe threads stripped

[Banthafodder]

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

 

[Stoneman]

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

Studs are ideal for the exhaust for this reason IMO
If the studs are seated properly (I like to use a loctite) you wont have that issue.

Seen it a few times, Allan heads look neat but important to keep them tight.
You could try tapping to the next size or a helicoil.

 

[Banthafodder]

thank you stoneman just the answer i needed i just googled tapping and i guess i can drill in and make it the next size. in the pictures you can see that there is a large chip taken out of the corner. about 4 or 5 threads are missing from one side would it be safe to drill it any deeper, and if so how much? would this even be an issue?
thanks again for your reply

 

[mattrgray]

Tapping to the next size may not always work, I tapped mine to m8x1 and after a little bit it cracked the cylinder. I've never tried a helicoil but it seems like it might be worth a try to save your cylinder.

 

[Stoneman]

Yes you need to be mindful of the limits you have depending on the jug casting
So I would avoid going deeper without serious consideration.

On the cdh pk jugs we had no issue going to m8

Only bonus with a helicoil, if it’s well done you well end up with a possible stronger thread as it’s steel, stainless it think.

 

[Stoneman]

than try loctiting a stud in there to eliminate it coming loose

 

[FurryOnTheInside]

I would use red loctite to permanently fix the stud in the partially stripped hole. (Actually the stud would be a decent grade M6 bolt with the head sawn off.)
If the intake stud spacing is 32mm then the cylinder is inexpensive to replace (check ebay) so I would have no hesitation in recommending RED (permanent) loctite. Otherwise maybe use blue.
To be thorough and to protect your investment, you should have/make a bracket of some sort to support the weight of the muffler and take the strain off the exhaust studs.

 

[Timbone]

First, going forward you must rig up some kind of muffler support for your exhaust. If you ride without one, you can expect failure of the exhaust studs.

If I suffered, say, a complete failure of both exhaust studs and had no money for replacement, I would weld two pieces of 1/4” rod into the exhaust bolt holes and slide them into the stripped bolt holes on the jug. Weld a couple of attachments onto the exhaust and then find a way to attach the exhaust via two string springs onto the engine. Lots of motorcycles use springs to hold the exhaust

 

[Banthafodder]

Thank you all for your replies. Just an update I've bought myself a drill and some loctite. Im going to attempt to tap the screw hole one size larger. That is after i practice on some scrap metal and learn how. I saw some other great suggestions but i lack the knowledge and any of the tools required.
I should get to it before the weekend. Ill let y'all know how it goes. Until then im open to more advice if theres anything i should know before attempting this.
Thanks again all of you have been a great help!

 

[FurryOnTheInside]

Thank you all for your replies. Just an update I've bought myself a drill and some loctite. Im going to attempt to tap the screw hole one size larger. That is after i practice on some scrap metal and learn how. I saw some other great suggestions but i lack the knowledge and any of the tools required.
I should get to it before the weekend. Ill let y'all know how it goes. Until then im open to more advice if theres anything i should know before attempting this.
Thanks again all of you have been a great help!

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.