RE: What's the right muffler for my TT 40 pro??
Buzz is right. FWIW, I've been gluing them together with JB Weld and relying on the through-bolt ONLY as a backup device. That is, I don't tighten the through-bolt very tightly at all.
I think the reason these mufflers come apart is that when they're assembled, there's already a lot of tension on the through-bolt. Then the muffler gets hot and expands, which increases the tension until the through-bolt finally snaps. And since there isn't anything else holding the back half of the muffler on, it usually gets lost.
Gluing the parts together with JB Weld is a good semi-permanent (maybe permanent) method of holding the parts together. But if the JB Weld fails, the through-bolt is still there to keep the parts in the same county until you get a chance to fix it.
Just my .02 ...
Duane Gall
RCPRO