2000 sporty custom pops through carb

[cajun1957a]

My son has a 2000 883 custom.  9500 km on the bike.  (Canadian).  The only mods done to it is the Screaming eagle pipes and air cover.  He is experienceing issues with his plugs and has replaced them twice now.  The motor runs fine on the highway, but intown driveing results in a spit or pop  out of the carb when accelerating from a light or stop .  If he turns off the motor and restarts it, it will sometimes pop out of the pipes as well for a second. 

I have heard that jetting should be done with the screaming eagle set up.  Is this correct?  What should he look for?

randy

[mayor]

yes, the pilot jet probably needed changed. The popping is generally a sign of being lean.  Either the idle air/fuel screw is not adjusted right, or the pilot is too small, or the needle needs shimed a hair.  The needle would be the last place I'd look. 

See if the plug is still covering the air/fuel mixture screw (bottom of carb near the intake manifold).  If still there: you can remove the plug by drilling it with a 1/8" bit, screwing in a sheet metal screw, then pull the screw with a pair of pliars.  Turning the screw in leans out the idle AFR, turning out richens up the mixture. Adjust the screw out until the engine starts to stumble at idle, if the engine doesn't stumble by 3 1/4 turns (3 1/2 turns is max) out change the pilot jet.  If the engine stumbles before 3 1/4 turns , turn the screw in until the engine starts to stumble...then split the difference (I generally run my idle towards the richer side)

If the pilot wasn't changed it probably has a 42 pilot jet.  I usually switch that to a 44 (available through aftermarket only), or a 45. If you need to change the pilot, adjust the new one with the above method.   

hope this helps...

[Hillside Motorcycle]

Great advice from the mayor.
Scott