Coughs and spits. After I totally warm it up it will idle ok and seems like problem is gone but when I turn it off for 15 minutes it will start backfiring all over again. Carb has been rebuilt by Harley dealer and myself prior to that. Could it be an electrical problem. I am lost. This is a 98 carbutator road king. I installed the yost powertube kit and it ran great for the first day then started doing the bad idle again. I also flushed the tank. Any suggestions on whether it could be electrical. Once warmed up totally seems to run ok.

 

kinda sounds like the metering circuits are still plugged. it may be VERY difficult to fix this.

i hate to say this but if the tank is clean, you may want to consider trying another carburetor.

 

whats your jetting? have you checked for intake leaks? if the carb has been on and off several times, id start there. sounds lean so definitely check for leaks, check fuel supply and float level, accelorator pumping?

 

Thing is, when it's running it is running awesome. It won't start acting up until it has time to cool a bit and I fire her up again. If I don't reve it on and off sporadically it won't hold a steady reve without farting and coughing. Even at a high rpm reve. I have to keep gunning it hard on off for it to warm up enough to work and idle properly, about 10 minutes of gunning it on and off. Choke or no choke, same thing. Before I could always release the choke and set the throttle at a descent rpm and just leave her to warm up.??????????? Dealer is going to bankrupt me. Any more suggestions.

 

leaking intake manifold seals?? might be worth a look.

 

Sounds like what Mentor said.
Scott

 

How do I check that? Just by eyeballing where it meets the jugs it looks fine. Tried to start her up again today same thing. After it warmed up it ran perfect. :-(

 

after its warmed up, spray a little carb cleaner on them from the left side of the bike, where the intake meets the heads,if the idle races even higher, thats a place to start.

the engine wants a richer mixture when cold, an air leak would offset this balance between the enricher and the AF ratio and could cause the poor idle.

there could be a tear in the o-ring behind the carb too.

 

My vote for either an external of possibly an internal vac leak. Missing cap plug even. Pull the plugs and see what color they are. Black = rich, white or light tan = lean.

 

Intake gasket