I have an OS 120 FS and the exhaust thread to the exhaust arm is so loose that no matter how tight I tighten the nut, after some vibration, when the engine is on, the exhaust will work itself free. I have used some pipe sealant but it still comes loose. I am thinking of putting some hemp fibers on the thread and than screwing the exhaust to give a better grip. Will that work? Any advise appreciated.

Clean all parts with Acetone and reassemble using some high temp. Loctite.I use is Threadlocker # 294.

Look here > http://loctite.com/int_henkel/loctit...d=114&layout=3

And here > http://permatex.com/products/prodidx...=Threadlockers


HTH

Teflon tape works great also.

Hello; I have used a paper clip to substitute for worn threads. Try One piece in there, and if that doesn't do it I've used as much as 5 little pieces held in there while I tighten the two pieces together. The paper clip will conform to the threads and lock them together if they are that loose. That trick will work with sheet metal screws too. I have made an insert to press in to renwew trheads, that fixed it permanently.

It's too expensive to replace the head just to renew the exhaust port threads.

LOck Tite make a product called Quick Metal that might work, i haven't tried it, it might not be able to withstand the heat. The idea is that you smear this stuff on both parts then assemble it and wait for it to harden. I have used it for pins that got loose in their bore, it works fine for that.

Thanks for the suggestions... I will heat it up before tightening and use some material to give a better grip to the thread