I've got an 81 with an S&S Super E shorty on it. No matter what i do I can't get the carb adjusted right. the carb came off of another Ironhead that was running perfectly. It was running fine for a few hours then started losing power and backfiring really bad in 1st and 2nd. I put new plugs in, retuned the carb to s&s reset specs then brought it to operating temp and tuned it in and bam it was perfect. I checked for intake leaks. none. She was running great for an hour or so then went to crap. I checked the plugs and the were black so I cleaned them and tried it again. Still horrible. I had some more new plugs so I figured I'd just try them. It ran perfect...then crap after riding for 30 mins.

I'm stumped. I guess next I'll try some different jets on it but I didn't think I would need to as it was fine on the other bike.

Any help would be greatly appreciated. Oh and I'm new here. Thanks.

 

turn the acc pump almost off it flooding the engine every time you turn the throttle

the oil might have a gas smell to it as well

 

Running well then not well when warmed up is a classic symptom of a bad ignition coil or a bad ignition module. There are no really satisfactory tests for either of these components.

You can fool with the reg using a hair dryer to heat it up or canned compressed air to cool it down hoping to create or remove the overheat condition. IMO best to just buy a new coil. If it does not fix the problem keep it - a good working coil is a useful tool to have for testing.

There is virtually no way to test most ignition modules, altho there is an 8-step troubleshooting procedure in the 99484-85 Factory Service Manual for the 80 to 82 module. Again, best IMO is to buy a new one.

The Ultima kit with both an ignition module and a matching ignition coil is often on eBay for $154.95 Highly recommended. I think this one has expired but it will come up again ...
http://cgi.ebay.ca/ws/eBayISAPI.dll?...m=261557832099

 

I'll give that a shot and see if it helps. Thank you.

 

I had a feeling that might be the case. Thank you!!