so im working on a friends sachs g3 with the 75cc kit gianelli pipe. my friend daniel used the wrong bolts and stripped the holes so i had it retapped and helicoiled. the bolt/washer configuration didnt work out too well as the bolt kept vibrating loose so i put green loctite and ground down an allen bolt ( what it originally had ) to work.. another reason i think the pipe kept coming off was that the rear mounting bracket my friend had wasnt sturdy enough. as a matter of fact it didnt really suspend it at all. so that exhaust is kickin around chewin up the manifold against the cylinder. i cut off the little mounting bracket in the rear and rewelded it to the proper place and used a flat piece of metal as an extension to bolt it to one of the sidecover bolts. now this thing held real sturdy and didnt budge one bit. today i test rode it for 15 minutes and i know the engine is vibrating real hard and the pipe (where the header clamps onto the flange) just snaps. so now i have a flange bolted to the head and no neck.
can someone tell me whats wrong and why it did that? are sachs engines supposed to flex? did i make that mount too rigid? ive only really worked on puchs and never had a problem like this. please help me!