Hello HD Forum,
Just installed an Mreed DIY air cleaner (thanks, Mreed) on my used 1999 883. Already had screaming eagle slip ons for the past year. Took it for a run before digging into the carb and it ran like a beast (compared to stock a/c). Way better response thru the whole range, noticeably had more *****. Idles great. However, I Did develop a carb fart that I did NOT have before. It seems to be at cruising speed right around 1/4 throttle. It's not too frequent. Happens probably 10-15 times on a 1 hour ride. I decided to look in the carb. Plug was already removed on mix screw @ 2 turns out, slow jet was at 45 and main jet was at 160. Also, the spark plugs indicate a pretty good a/f mix. I've done hours of research but can't seem to find MY answer (despite the thousands of pages of great info on this forum). I've read the Harley-performance tuning and jetting instructions but can't quite figure this one out. Truthfully, the carb farts don't bother me THAT much considering how infrequent they are, but ideally I'd like to get rid of them.

What I'm thinking, because of where the carb farts are happening at cruising speed--around 1/4 throttle, that it would be the slow jet, but it's already at a 45. Maybe my logic is totally wrong. All in all, I'm new to Harley's and carb tuning, but I'm not new to riding or wrenching. Hopefully someone can help shed some light for me. Any info or thoughts would be GREATLY appreciated. Thanks in advance HD Forum!

 

I re jetted the carb on my 883 some time back using CVP tuner kit. It was sneezin and fartin like crazy. I just got the paperwork out and they recommend on their chart for an 883 Stage I filter/exhaust a # 44 Idle and a # 175 for the main. They have more info on their web page that might help ya. It really cleaned my carb up. http://www.cv-performance.com/

 

So how many turns out on the mix screw,usually you back it out 2 1/2 turns and work from their about 1/8 at a time.

 

Thanks for the input, Frankenbike.

 

My carb has stock jets. Under 5k it farted a lot. Now it rarely farts after about 15k miles unless its under 40F then it does still fart until its warmed up.

 

The mix screw was already at 2 turns out. Maybe I'll try bringing it out 1/8 turn or run a bigger main jet as frankenbikes info suggested. The thing is, it idles and accelerates like a CHAMP so I don't want to get things too out of whack. It carb farts a dozen times per hour-long ride, mostly while cruising in the 1/4-1/2 throttle.

 

If it is at cruise, it's most llikely the pilot circuit. Just back the screw out 1/8th of a turn and see how that goes for a while. You can back it out all the way to around 3 turns before you start needing to worry about jetting higher.

 

Yes the slow jet would have the greatest influence at 1/4 throttle but fuel is still being drawn from the channel leading to the mixture screw (I think). Get a flathead screw driver and mark off where you have the mixture screw currently by placing the screw driver in the hole and marking its edge with a marker on the carb. Turn counterclockwise 1/8 to add fuel and keep adjusting and test riding. If the problem doesn't go away and you feel that your first seconds of acceleration is being effected badly than try changing your slow jet. Depending on the company from you bought your jets, the measurements can be inaccurate. Also you might want to check for intake leaks. Float level (if ypur taking out the carb), also check that the vacuum line is not being pinched as well

 

Thanks, scuba and knights2theEnd. I've backed out my mix screw by 1/8 turn. I'll take her out today and see how it goes. I really appreciate the help and input from everyone. Thanks.

 

+2 on adjusting the idle mix screw for the carb fart.
BUT IMO, the 160 main jet has got to be too small for a stage 1. I'd up it to a 170 or 175.