2001 carb softail. runs good cold. after it warms up it starts to missfire or run bad. tried the ignition coil and crank sensor. replaced the plugs. rebuilt the carb. checked the stator and regulator reading, all ok. drained the gas and replaced with fresh gas. replaced the screen on the petcock. I don't know if it could have caused a issue but the last time it was running good i got caught in the rain, came home parked it. the next time out it started running bad enough i had to call for a trailer to get it home.

 

The new ethanol gas is hell on anything rubber. if the needle valve seat is made of rubber, I would look at that. Rubber can swell to twice it's normal size because of the 10% ethanol in the gas. If this happens your bike would run OK for a few minutes, then it would start to starve for gas and run like crap.

 

Not totally true... I have been running REGULAR GRADE 10% ETHANOL GAS in my 03 for 7 years and 71,000 miles and have never had a problem. I religiously change the engine oil with the brand of the day synthetic 20-50 wt, primary ATF type F brand of the day, and Tranny lube brand of the day synthetic 75-140 wt every 10,000 miles or so... the problem at hand for "greenmac" is probably still one of moisture. Water in the fuel system is easily taken care of with the brand of the day "fuel dry" and taking a trip that uses most of your fuel... these are motorcycles not babies... they are just machines and cannot tell the difference between brands of products and cannot tell time. It's all in your head not your bikes... "Ride it like you stole it".

 

could a bad ignition module cause this?