Expert: Mike Wells - 10/15/2006

Question
I have a 89 softail with stock keihin butterfly carb. First of all it runs rich (someone else jetted carb). It has a k&n filter and ultima big growl 2 1/4 inch pipes. Does the idle mixture screw richen by screwing it in or out. What do you think my jet sizes should be. Bike runs o.k. but plugs are black and black smoke is visible during idle. Plugs will foul with excessive idling. Long rides are not a problem but plugs are still black. Do you think I should stay with this carb? What would your choice be foe a replacement?  Thanks,

Mike

Answer
the mixture screw only works when the bike is idleing. Turnin it inward leans it. warm the bike up and slowly turn the screw inward, just until the bike starts to stumble then outward about 1/4 of turn and its set.
If youa re fouling plugs then you need to go leaner ont he inermediate jet. remove the jet and check the size and go one small. Keep doing this until you get it not to foul plugs.
If I were planning on changing carbs I would go with the S&S. Good flow and easy to install and jet
Good luck and happy riding
Mike