1995 Sportster 1200 XLH - Cleaned the carb bowl, needle, plate. Hardly any residue in these parts. Did not clean the float or float needle as they looked fairly clean. Runs much better, but still won't idle unless the choke is at least slightly open. When rolling the throttle in neutral, slight hesitation in the lower RPM range. When accelerating or maintaining speed in third or higher gear, it hesitates and/or backfires. Could this be caused by the carb or is there another issue possibly causing the problem?

 

well, sounds like the pilot circuit which controls idle and mid transfer. could be needing an adjustment or a good cleaning. the lean out causes the cough. also the accel pump not working will cause a stumble with a loaded roll on. the transfer ports are extremely small and had to clean and if the carb set up long term, oxidation could permanently screwed them up, aka, paper weight.

 

Thanks, Bustert. I’ll give those items a try.

 

I have a 2003 XL883C Sportster bored to 1200. Mine is doing the same thing but it isn't constant. I rode the other day for about an hour and a half with no issues. Today I rode and it kept bogging down like it was running out of gas and kept jerking. And it backfires as well. I have ran SeaFoam through it in case there was moisture due to sitting over the winter. I took my air filter out and am cleaning it. I think I need to have my carb looked at.

 

Air leak at either the carb, or intake manifold to cylinder head connection. Check by using WD40 spray. Spray around all fittings and listen for engine rpm change.

The rubber gasket that connects the carb to the intake manifold sometimes will blow out in only one back fire through the intake. Pull carb and check to make sure it isn't split.

A back fire through the carb is a lean condition, through the exhaust a rich condition.

 

Hesitates, backfires, sounds like my x wife

 

Thanks Kabear. I'll try some of those. I really appreciate the response.

 

One item I forgot, if your bike has a MAP sensor check that gasket also. Located on top in intake manifold where it splits to front/rear cylinder.

Next item would be the CPS(Crankshaft Position Sensor) may be going bad, mine would run then just quit until the sensor cooled off, then start right up and run like nothing was wrong until it heated up again and the it would start cutting out and eventually quit. I had always associated a "hard" miss with electric and a "soft" miss with fuel until this item started acting up.