I have an 03 fatboy,converted to carb, has a basic Harley carb , turned on and idled fine, and then I went back to turn it on a few minutes later and it started having trouble starting,I gave it throttle and it stays on but has a bad misfire, sounds like very loud popping ,and as soon as I let go of the throttle it dies ,jets not clogged,I have no leaks, plugs aren’t wet , I have no idea what it could be . Help!

 

Could be a bad crank sensor. Let it cool off and try again. If it starts right up, bad crank sensor. I'd also check the plug wires. Make sure the ends are clean and no cuts.

 

I put a new crank sensor ,new wires ,new plugs , coils good, still not working. I noticed it only starts when I twist the throttle ,choke doesn’t make a difference, and soon as I let go of the throttle it dies. So it’s getting spark

 

Does it sound like it's running on both cylinders?

Plugged pilot but choke should still work..

You may want to try a compression check. You might have a stuck valve.

 

If you just did the conversion and the problem started, go back and check what ya did. Intake manifold seals leaking? Does the enrichment (choke) system work? Does the accelerator pump squirt gas when ya twist the throttle? Twin Cams have Single Fire ignition . . .are the plug cables reversed?

 

I think one thing to note is that the bike won't run at all, if the plug wires are reversed.

 

Does it have a carb coil or efi?

 

EFI, I’ve had the bike a year,ran no problem at all.

 

the conversion was done way before I got the bike, I e had it about a year, and never had an issue, til just recently the battery started to drain ,and I started having this misfire issue since about 2 days ago. It just seemed so weird that it started up perfect and ran fine and then it starts misfiring this bad out of no where.

 

The wires aren’t crossed, the carb spits gas when I twist the throttle but bike dies immediately after I let it go ,choke works ,plugs have spark,wires are new , crank sensors new, still misfires ,sounds like gun shots