I just picked up a 2006 FXST and have a few minor issues with the carb. It has V&H Big Radius pipes and what appears to be an open element air filter hiding behind the stock cover. The bike only has 4200 miles on it. The dealer I bought it from had no records as far as the modifications go other than what can be seen. Some times it will idle down smoothly like it should and other times it will idle up around i'd say 1200-1500 rpm's. The bike runs smooth and has plenty of power. Occasionally while setting at idle the carb will kinda sputter for a split second then go back to normal. This reminds me of my Sportster I had and it's notorious carb farts. As luck would have it, it's been raining almost every day since I picked the bike up last Thursday so I haven't had much of a chance to tinker with it yet. I'm thinking maybe it wasn't jetted up after the exhaust and A/C upgrade???? Or possibly an intake leak somewhere???? Any ideas on where to start looking would be greatly appreciated.

 

sounds like a int. leak,spray some carb cleaner around the int seals and see if idle changes (if it dose,you have a leak)

 

i agree w/ prodrag , try spraying some carb cleaner around the intake gaskets (at the head), with the motor at idle , if it stalls out there's a leak in that area, also ,pull the slow jet and blow it out w/ compressed air, see what size it is and go up one size from that , then put the mixer screw out 2 1/2 turns from seated .....while you have it off ,clean the air filter and dry w/ the air also ....

 

Thanks guys. As soon as I get some free time and its not raining I'll give this a try.

 

Same bike I have, high idle and random carb farts are indications of lean condition or intake leak:
Step 1- get a service manual. Remove and check spark plugs for color.
Step 2 -Spray carb cleaner around intake seals like prodrag said.Run Seafoam through it.
Step 3 - take off carb and see if the plug covering a/f mix screw has been removed. If not, remove and then take off bowl, then jets to see what sizes are in there. You should probably have a 46 or 48 pilot and a 190/195 main jet. You may have to adjust the float, the procedure is in the service manual. Google tuning a CV carb for adjusting the a/f screw. Getting the right jets is a matter of trial and error, trying different jets and evaluating spark plugs. Or, it's easier, less time consuming and more precise to take it to your local tuner that has an exhaust sniffer and dyno and can tune it that way to get you to an a/f mix of about 13.8-1.

 

Well, I had a chance to tinker a little bit last night. I sprayed some carb cleaner around the back of the intake and notice a minimal change in the idle.....without a tach its hard to say, but judging from my old bike with a tach, I'd say less than 100 RPM increase when I sprayed. The general consensus is that the idle should sputter when you spray if there is a leak from what I understand. I had a complete stock A/C laying around so I swapped that on and that made a HUGE difference in the idle. I set the idle and took it for a cruise. The idle settled down smooth every time and the card pops were virtually non-existent. I went ahead and ordered a new set of intake gaskets and got the hook up on jets from a local wrench. So as soon as my new manual gets here I'm going to tear in to it and jet it up and replace the intake gaskets just to be on the safe side.