I was wondering if anyone can tell me if there are different versions of the Muscle Pipe II. I have one on a YS80 in my X-Cell 99 SE and just cannot seem to get the engine to run good with it. I am running a 8.45:1 gear ratio with 690mm blades and using Wildcat 30% fuel. The needles are very sensitive and a couple of clicks either way is all I have between being too rich or too lean. I have cleaned the carb, checked over the entire fuel system as well as the regulator for leaks ect and everything is fine. I even replaced the fuel line and installed a new OS #8 plug as well as new check valve. It seems like no matter what I do the engine does not want to run smooth and makes a ratty sound from the pipe no matter how I tune the engine. It is even running a bit on the hot side. If I set the hover needle any richer it burbles a lot and runs even rougher. All adjustments of the hover needle are being made a 40% barel opening as called for in the instructions. The engine has had some run time and is not new but is in good shape. I have also tried a higher head speed after getting it as best as I can at 40% barrel opening and it still runs rough if not rougher.
This morning I decided to try a KSJ YS61 muffler I had just to see how things would be with it. The engine ran a lot smoother and was running way cooler with the same needle settings. The needles were still sensitive but the 61 size muffler may not be helping as it is a little restrictive for the YS80.
A buddy of mine has a YS91 with a MP2 and I noticed his MP2 sounds very different then mine. Mine has more of a tuned pipe sound compared to his. I also have noticed his has Curtis Youngblood engraved on the side of it where mine does not.
I have owed a couple of other YS powered helis that had hatori mufflers and they were very easy to get tuned compared to theis YS80/ MP2 combo.
I am open to any ideas to what may be going on or suggestions on what to do. I have already started looking for another muffler as I am starting to believe the MP2 is just not going to work.