I own a 1990 FXSTC. I just purchased this bike and it is my first Harley. I am having a problem with the bike back firing threw the carb when the bike is trying to maintain speed no matter what gear I'm in. The bike runs great as long as I'm accelerating. The bike is stock and has duel fish tail pipes.
I just went to get it smogged and it failed the Hydrocarbin test with a reading of 2201 ppm if this helps in any way.
Does any one have any ideas. I would greatly appreciate any input that can be offerd.

 

Hi az. I have a 94 FXSTC which I bought new. It does't backfire through the carb, but it does sometimes seem to starve for fuel. It happens normally just after I start the bike, warm or cold. I havn't had it stall yet, it just seems to miss a beat. It's always done this, so I'm prepared for it when it happens.
I hope you can find your problem.
Cheers

 

My 883 sporty was doing the same thing and my dealer shimmed the needle in the carb ?

 

Hi jt. Did your sporty backfire or starve for fuel??
Thanks mate

 

Shimming the main jet needle up with 2-#4 brass washers will cure your problem

This link will give you some insight

http://www.nightrider.com/biketech/hd_cv_mods.htm

 

Had a 92 fxstc and it did the same thing out my S&S

 

This graph will give you an idea of when the different circuits are feeding the carb.The second one down is the one that you would richen by shimming it as stated above to eliminate the popping back in the cruise range

[IMG]local://upfiles/2318/3FFB3DA99E88401380C9448A7E7DCC0B.jpg[/IMG]