my 929 has a yoshimura slip on pipe.does every one have a power comander on that has after market pipe.when you rev the bike up to around three grand and hold it there you can hear a little stumble in the engine . plugs look fine bike seems to have alot of power.Im just worried it might be running lean.the engine seems like it has to much vibration, I think it should be a little smouther. any help would be appreciated.