I have an ASP 1.08 and am happy with it, although with an OS 7D carb Im not happy with low speed performance, loads at idle. ( I am probably trying to idle too low)I went back to a stock muffler from a pitts style and got improved dependability. Also I tried centering my tank on the carb. I am a big supporter of run it with as many oem parts as possible because it had to work at the factory. My carb change was due to a missing carb when I bought the motor and I had an extra 7D in the drawer. I have one full season on the motor and no dead sticks. Good luck on finding your glitch...