Ironhead 85 xlx running underpowered then fine

[morkrazy]

i'm very new to harley repair, but a relatively bright guy with a wrench in my hand.
i have an 85 xlx and when it's a cold start it runs underpowered. seems to be running on one cylinder for the first few minutes after taking off, then it takes off and runs great. it's fouling plugs repeatedly and it seems to be going from one cylinder to the other. front will foul, then the rear will foul. niether will oil foul. they always end up sooty not wet. ive checked/repaired exhaust leaks and replaced intake seals. torn the carb apart and cleaned everything and verified the correct jets. checked compression 165/175. adjusted the lifters to the specs in the manual. im starting to think this may be an electrical issue. i get spark from both sides of the coil, but could this be a VOES issue? ignition module? ignition sensor? is there anyway to eliminate which component may be failing without replacing them one by one? also, as i seem to be going through plugs every 30-250 miles is there any plug in particular that you guys would recommend? Champion RL82YC seems to have given me the best results so far.

[morkrazy]

I forgot to mention it backfires through both pipes when it's running rough, not at all after it picks up and runs smooth

[ryder rick]

idle mix gets set to HOT lean best idle.
Cold running on one cylinder could be valve adjustment (needs to be done stone cold).
You don't say what ignition you have, generally the black box OEM modules rarely fail but the sensors do. Hard to diagnose intermittent problems, the manual has instructions to test. Barring that the only way to really find out is substitution, I would throw a sensor at it if the wiring and such is good.

[morkrazy]

It has the stock ignition to the best of my knowledge, I haven't drilled out the rivets yet to see what's inside

[76_iron]

Did you do a bubble test when you replaced the intake seals? What carb are you running? Some of the keihin carbs had the accelerator pump rod too long and would trickle gas at idle.

[morkrazy]

I have a sudco mikuni vm 38 carb, I ran around the intake with propane after changing the seals and had no changes in rpm

[dablues61]

I had similar problems with my '85 when i tried adjusting the pushrods without letting it get all the way cold.

[morkrazy]

It was 110 in my garage when I did the pushrods but it hadn't run in a day and a half

[morkrazy]

Problem solved! I ordered a new ignition kit and installed it, it's running much better, not missing and not running rich like it had been! I don't have a timing light so I set it with the static timing instructions and I'd say it's awful close to dead on and running great!

[hugie03flhr]

I usually increase the timing 1-2*+ until you hear pinging them back off 2*