Jorge - There is alot of vibration when breaking in the engine. I've noticed recently that the more fuel I put through it, the better its getting. Since I have the pitts style exhaust, I dont have the through-bolt, but I did thread lock the mounting bolts. Have not had any problems with it. I also thread locked everything else .... eventually getting to the carb. Dont know why I skipped that at first ... dummy me. LOL! Also, make sure your prop is balanced.

What kind of plane are you putting the TH75 on? Dont recall you mentioning that ... maybe you did. [8D]

FlySafe! Larry (Larrys4227)