I'm a newbe to Harley's, and I just bought an 05 XL. It coughs at take off. It does this even after I've been riding for a while. When I run with the choke out a little bit, it'll stop coughing. It also seems to run better this way. Could it be that the choke needs adjusting? Oh yea, by the way I've also been told that by running with the choke out it will foul my plugs. Is that true or is it a myth? Should I just take it to the dealer to check her out for me? Any input on this matter would be greatly appreciated...

 

Riding with your choke on will foul the plugs. If the bike sat very long before you got it, the carb may need cleaning. Has the air cleaner or exhaust been modified (stage 1)? If it has it may need to be re-jetted.

 

run a bottle of carb cleaner thru it first, and see if that helps

 

Sounds like you might have an intake leak. You can take some carb cleaner and while the bike is running spray it in from the aircleaner side making sure not to get any into the aircleaner and spray on the intake where it goes into the heads. If the idle changes at all then youve found your problem and need new intake seals.

 

Thanks for your responce..As far as I know it hasn't been modified.

 

It's running lean that's what causes bikes to cough back through the carb, that also explains why it runs better with the enrichener out a little. All stock Harleys do it to some extent.
The real fix is to get the plug off the idle mixture screw so the carb can be adjusted or you may also need one step larger idle jet.

 

The way to correct the carb cough or as some people call them carb farts, is to rejet the slow jet. The stock slow jet is a #42. You can try a #45 and if the bike has pipes and upgraded air cleaner, than go with a #48. I run a 48 in my 01 1200C. it has SE II slip ons with big city thunder baffles, 180 main jet, 48 slow jet and a hypercharger. No carb farts at all. Good luck

 

He said his bike was all stock so it shouldnt be doing that. Its always a good practice to check the intake seals even if it did have pipes and aircleaner on it as its runs slightly lean stock anyway for emissions purposes and will cause the intake seals to get hot and go bad.

+1 This is correct on the jetting. Although as i stated above check for intake leaks before rejetting.

 

My 2006 does that a bit. I'm running some Sea Foam through my tank of gas thinking maybe the pilot jet is a little dirty.Mine used to do it a little only when cold and just off idle. It's got a bit worse I noticed just recently.

The dealership I work at, the techs often go to a 180 main jet, 45 slow jet, and go to a "California" needle. I'd rather leave me jets alone, so I'm going to try the Sea Foam. My bike starts well, and runs fine otherwise, and I got it used with 3000 miles, but I think it's all stock.

jon

 

A Dynojet or Thunderslide jetting kit helps a lot with the cough. The stock needle is not adjustable so the kits generally come with an adjustable needle as well as other jets to get it tuned right. Pulling the idle screw plug so you can adjust the idle mixture is a free way of getting some adjustment if you do nothing else.