Popping and cracking on deceleration? and/or when I cut the throttle. Does this mean lean or rich? I just added and exhaust sysem and nothing else so I would figure lean but it then sometimes backfires.
Its running lean. Assuming your talking about the Chromo.......I think the were injected for 01. You can make slight adjustments at the fuel mixture pot (I can never remember which way to turn for lean and which way to turn for rich). If I'm wrong about the injection for 01, go ahead and mod the airbox and then jet kit it........you will be happy with the results.
When my bike was doing this, it was first suggested that I may have an exhaust leak. Turned out to be fuel (lean), but it is something else to check. The shop used Permatex copper gasket spray on the pipe joints to be sure.
My bike (2000 900M) does the same and it can be partly cured by using a lower octane rating fuel. In Australia we only have unleaded (lower) and Premium Unleaded. It definitely pops more on the premium.