Engine Trouble Bolts keep falling out.

[SerHofi]

So I have a 2 stroke, I got from someone on Facebook Marketplace.

The engine runs well. But after about 10 minutes of riding, the bolts holding the carburetor and the muffler come loose and fall out.

I have tried using locktite, tried different headed bolts so I can apply more pressure when tightening. But no matter how tight they are, they seem to vibrate out anyway.

Anyone have any idea on how I can keep this from happening? I have gone thru about 6 sets of screws/bolts but no luck.

Any help would be great. Thank you.

 

[ImpulseRocket]

Find some gap filling loctite

That's what all loctite does.

 

[Chainlube]

Find some gap filling loctite

Plumbers goop and spit.

 

[darwin]

Are those head bolts course thread? If so maybe tap them to a machine thread.

 

[Wrench]

Course threads are better in intake and exhaust manifolds

China Girl engines intake and exhaust threads are 6mm x 1.0 which is a course thread
BTW 6mm bolts only come in 1.0mm

But when 6mm threads pull out and a helicoil isn't necessary, they're commonly fixed by tapping the hole to the next size bolt which is 1/4" It's so close ya don't even have to drill the hole, just tap it
1/4" bolts come in different thread pitch, course and machine, but 1/4" x 20 is more course than 6mm and will have less chance of the threads pulling out again

So when @SerHofi strips out the threads from over tightening, he'll now know how to repair them