I have a 1998 Fatboy and my question is, I put a Arlen Ness big sucker air-cleaner on it but even before that my motor would backfire every now and then, most of the time when I let off the throttle when I'm slowing down but if I pull the choke out just a little bit it runs perfect, not the first backfire, any ideas? Maybe needing bigger jet?? Right now I have a 180 main jet. Thanks for any info on this.

 

I'm not an expert, but I'm dialing in my bike and getting advice here. Sounds like a pilot jet or mixture screw issue (if it's only jetting). What pilot jet do you have? Probably go up a size. And then reset the mixture screw, probably a quarter to half turn out?

 

backfire thru the exhaust is too much fuel, thru the intake too little gas duhh I think could be basackward. someone check me I need sleep.

 

Check your intake seals. Make sure you're not sucking air there... And is it backfiring or popping on decal.....? up the pilot jet 1 or 2 sizes and readjust the mixture screw. Should be 2-3 turns out if it's a CV carb....