Will someone help me? Ive installed a full leo vince gp pro system on my bike and since that it was running horrible and lumpy, lost about 20mph of the top speed, barley getting 100 miles out of a tank, i recently put a power commander v in hoping that this will help everything when it hasn't, it has only given me a few more miles and the speed remains the same. Can someone please help! Thank you

Have you changed the jetting? normally if your fitting a more free flowing exhaust you have to change the jetting to suit.

Pull a plug, if its brown your too rich, if its white your lean. (if its lean i wouldnt ride it unless you put the original exhaust on or change jetting)

I wish i could change the jetting but its fuel injected! And cant get to the plugs without a special yamaha tool