My excellent condition '05 XL883's front pipe is leaving soot in its new slip-on. The rear is clean. Both plugs have a little soot. Should I be worried? I'm assuming removing the restrictive factory slip-ons riched it up? Carb still has air/fuel plug in.

 

Removing a restrictive slip on should make the bike run leaner, not richer. What jets are you using? Open up that plug and set the idle mix screw to 2.5 turns out from lightly seated.

Sounds like a good time to rebuild the carb and refresh the intake manifold seals.

John

 

Very worried, your 883 makes so much real world powa you could be on the brink of Catastrophic engine failure with sooty plugs.

 

But if he would just put a 1250 kit in it he would be fine.