bsumpter

OK guys, I've ran it with the shortened header.

The problem is still there. I have to lean the engine too much to get it on the pipe. If I richen it to where it runs max RPM WOT, then it is too rich to come on the pipe from idle.

I turned the regulator screw in a total of about 1/2 turn (1/8 turn increments), and it did help some but didn't totally solve the issue. I've also noticed today that the exahust residue is a dark black -- a good sign that I'm too lean. The motor is also hotter than I'd like after a run.

So I defer to your suggestions. Should I shorten the header further, or lean the low end even more? This problem only came about once I had the tuned pipe installed -- it never exhibited these symptoms with the stock YS muffler installed. I'm hoping it's as simple as me having the header too long and further cutting will alleviate the problem.

Oh, and the black residue thing -- I put some of it on a paper towel, and I didn't see any metal shavings at all. It appeared to be pure carbon. Is it possible that the tuned pipe is getting hot enough to "cook" the oil causing the dark residue? Or is it almost a sure thing that I'm way too lean and damaging my engine?

All suggestions will be appreciated. I have a demo flight for a local handicapped center coming up on Wednesday, and would like to have this resolved before then. I don't think I want to run it this way until I'm sure that I'm not damaging my engine.

Thanks!

Brian