I ride an 03 sportster 1200xl custom. Two weeks ago it was running perfect, i parked it after a ride and it never started properly again. I assumed bad gas, dumped it cleaned the strainer replaced the gas. Traced the gas all the way to the bowl in the carb. Have spark on the plugs and a fully charged battery. Previously changed the plugs, plug wires and ignition COIL. When that didn't work I rebuilt the carb. Still has the same symptoms as when it originally wouldn't start. I turn the engine over and it does several different things. It will either spit out the carb, backfire like a shotgun out the exhaust, or smoke out the carb. The part that is confusing me is every once and awhile it will start from either messing with the air/fuel mixture screw or the idle screw. When it does start it runs better than it ever has (im assuming the carb had been due for a rebuild for awhile) it pulls strong sounds great idles perfect it runs completely flawlessly. Then I go to start the bike again and it wont start again. It NEVER starts twice in a row whether its still warming up or fully warmed up. I cant imagine the fuel/air mixture has anything to do with it because when it does start it runs amazing.

 

Check your VOES if it's malfunctioning your ignition may be advanced too much and cause some of the symptoms and difficult starting you describe.

Also check your plugs to see if you're running rich... though I'm guessing the VOES is your problem.

 

Right. Have you inspected or replaced the vacuum lines?

 

I will look into how to check the VOES. I have not replaced vacuum lines but did inspect them and found no issues. I cant use my plugs as a reference the bike only starts 1 out of every 100 trys so the plugs become fouled pretty quickly I'm on my third set of plugs trying to solve this problem.

 

Can you check your ignition module and circuitry. If it runs perfectly once in a while, something in the ignition module could be failing. Also check those vacuum hoses to the petcock and VOES. You mentioned cleaning the petcock assembly, maybe the vacuum hose got torn or damaged.

John

 

How many turns out on the mixture screw? 2 or 2-1/2 turns should be plenty to get it going.

 

I'm getting ready to work on a 2002 1200 Sporty. I would check the float level and the make sure the needle and float move freely. Sounds like like your flooding.
Just because your original problem stated as one thing (like dirt) then after the rebuild dirt or other mysterious force misadjusted the float. Its very easy to do.

 

How long has the bike been sitting? You may want to consider pulling the tank and washing it out. Just be sure to dry it out well.

 

Vacuum lines are good and the motor is getting gas for sure, the fuel mixture screw in the the range of 3 turns out or less. At this point I am thinking its the ignition module or VOES but I am still looking into how to properly check them for problems.

 

It turns out that the person who was assisting me didn't realize that the spark at the spark plugs was supposed to be blue, after checking for myself I realized it was almost orange. Any thoughts?