Hello. This is my first question on here. I have an 03 sportster xl1200c. About two weeks ago, it started running bad.

Out of nowhere, it began to sputter and run horrible while in downtown Ft. Worth. It would act like there was no gas, but the tank was full. Then it would die, sometimes running fine for a mile then dying. I parked it and put in octane booster because I suspected bad gas. Ran fine for about 10 miles, then sputtered a couple times but did not die.

The next day, it sputtered after riding for about 5 miles so I put more octane booster in, and no solution. It kept doing this after two more tanks, dying frequently on the highway while I had to pull over. I then suspected it wasn't bad gas, so I changed the spark plugs, placed a new o ring gasket on the carb, took the tank off, drained gas and checked the filter which was fine. Checked battery connections. Checked all other connections, fine. Rode great for about 30-50 miles that night, then began to sputter again.

Took it home and ran seafoam through it to clean out the carb. Rode down the street and pipes caught on fire from so much backfiring. Got it home, pulled jets, looked fine. Rebuilt carb. Cleaned everything. Ran it down the highway, was fine for about 4 miles then sputtering again. Got into town, no sputtering. It seems at times when I rolled on the gas heavy it would die out. Checked the coil and ignition module, everything to specs.

What are the conventional longevity issues with coils or ignition modules in relation to diagnosis?

Please help!

 

Change out the gas cap and if that doesn't fix the problem look at the vacuum operated petcock for proper fuel dilivery.

 

Thanks for the reply. I have taken the gas cap off on the road when problem arises, and no solution. Checked the vent hoses. All good.