[mgownr]

Hey All,

Searched but didn't find a good answer- My bike is as stated an 88 XLH883. The bike runs like a bear without the lights on, with the lights on the engine breaks up, pops, and spits. The coil, wires, and plugs are all new screaming eagle parts and we inspected the wire harness to the headlights, found one rub and fixed it. Took the bike out for about an hour and the problem came back. I thought it was a heat problem with the ignition but the problem came back this morning on the ride to work and as before with the lights off she is great lights on runs like crap. I am thinking about changing the remaining ignition components but would like some input on other cheaper potential fixes. Any help/advice would be appreciated.

[bikerjim1]

Really starting to sound like you have another spot on the wire harness grounding out. If you found one spot with the insulation rubbed, more than likely to have another. The fact that after you fixed that spot and it did well for an hour supports this. Re-check the ENTIRE harness.

[maxpower_hd]

Does it happen every time the lights are on or does it just seem like it happens when the lights are on? I had the same problem less the light issue on a 1989 XL1200. It would run great then start popping and farting out. This one seemed to happen more often in the cold. It eventually got worse. I replaced the ignition module and viola. Problem gone. If you know someone that has another Sportster, you can just swap it and see if it goes away. It's been a while but I think the Screaming Eagle upgrade was only $20 or so more than the original stock one. Maybe $65 instead of $40. I don't quite remember.

[mgownr]

It is def. with the lights b/c I can reach down and turn the switch to ignition only and the motor will bike right back up then act up again when I turn the lights back on.

Bikerjim1- I will look over the harness again, I didn't see anything last time but I was getting frustrated running up and down the harness. We (my father and I) thought it could have been a problem with wires in the headlight bucket so we fabricated a ground strap from the side of the bucket to the triple trees.

[Tumshie]

Could be the ignition switch itself is bad.

[mgownr]

We thought it was the switch so we got a new aftermarket and new harley one and the problem is still there.I went digging around and found a wire under the rear fender for the blinkers that was cracked and frayed so i replaced that and the problem still persists. I think I am gonna run a power power wire dedicated to the head and tail and have it run off the ignition only side of the switch so it will run with lights and I will be able to go to and pass inspection. Thanks for all the ideas everyone.

[chucktx]

how is the charging system, battery, regulator.......when you remove power from the ignition it will falter.......
chuck\
ps the charging system should be checked with all circuits energized.........

[CD]

Originally Posted by mgownr

Hey All,

Searched but didn't find a good answer- My bike is as stated an 88 XLH883. The bike runs like a bear without the lights on, with the lights on the engine breaks up, pops, and spits. The coil, wires, and plugs are all new screaming eagle parts and we inspected the wire harness to the headlights, found one rub and fixed it. Took the bike out for about an hour and the problem came back. I thought it was a heat problem with the ignition but the problem came back this morning on the ride to work and as before with the lights off she is great lights on runs like crap. I am thinking about changing the remaining ignition components but would like some input on other cheaper potential fixes. Any help/advice would be appreciated.

Wait a second. When the lights are off, she runs great right? That tells you the ignition is fine but the voltage to the ignition is crap.

Do you have the manual? Get the schematic out and start breaking it into the sub circuits. There are points you can isolate a circuit by disconnecting a junction block. Also, if memory serves this is a three cb system with the 30 amp feeding two 15 amps one for ignition related one for lighting. The 30 amp may be getting tired and cylcing.
Do you have a multimeter? It can tell you tons about where the voltage is off.

[hotroadking]

Have to agree with CD

You need a multi meter if you don't have one you can pick up one at wall mart or an auto parts store, lowes etc cheap, doesn't have to be the digital expensive unit.

Get the SM and follow the wires back from the headlight,

Pull the bulb check voltage with the switch there, does it idle fine and the problem only happen under riding conditions? Perhaps a wire is moving under something and shorting, or as CD says a breaker.

BTW you can get those HD breakers at any good auto parts store for about half price in most cases.

I would start at the ignition and see what voltage is, then out to the bulb, may have to pull the tank but with a meter you should be able to do voltage drop test and find the problem.