I've had trouble keeping the muffler mounting bolts on my Moki 1.80 tight. More then one occasion the bolts holding the muff on have loosened, and even lost one one time.
It's a Brison pitts style, very common for the engines, used by most from what I understand, and up until I put it in this plane, I had no trouble. It's in my Hanger9 Edge, stock mount for the engine.
I would use loc-tite, however, I've seen what that can do to aluminum, and am leary to have anything more happen to the mounting holes.
I'm thinking I'm going to get some lock-washers(metric, to fit exact).
Maybe I'm not tightening them enough, however, again, with aluminum(even the good stuff that engine is made of), I'm just very leary of damaging those holes. I'm pretty good at judging torque, and knowing when tight should be tight enough, however...it does seem, I can't get it tight enough.

Does anyone have any input, suggestions, or experienced the same thing??
Thanks guys!!

Read the thread BISSON MUFFLER ON A DA50 in the Gas Engines section for a lot of comments on this problem........RJ

Used lock washers and blue (meduim) lock tight on my moki 210 and it has stayed on for aprox. 100 flights. With blue lock tight it will not hurt aluminium.

Randy

One trick that always works for me is to tighten the muffler bolts when the engine is hot, or warmed up.

-Zip

Anyone know what size/length these are? i just lost one...

I have a system that works. On my Moki 1.80 I first CLEANED ALL THE THREADS of the bolts and holes using brake cleaner. When that's perfectly clean of all oil, then use blue loc-tite on the threads. Use Permatex Ultra copper sealant on the muffler and exhaust port to make sure the exhaust-to-engine mating area is leak proof. There's no way it will come off after that. Make sure the bolts are long enough, I use the one that BCM sent. Not sure what size they are.