#1 ELITE COMPU FIRE IGITION (settings needed) ?

shovelhead switched to "electronic" ignition?? "plugs & points" man, all my life... brand-new to me, so totally lost on this "improvement?". Hardly runs now, coughs sputter, backfires, wont run at all unless gas sprayed into carb ???? Had carb S&S shorty rebuilt, since 20 years old,???? suggestions?? please lol

As it is hard to understand exactly what you want, how about trying this website:
https://compufire.com/instructions-and-tech-tips.html

That said, your problem does NOT sound like an ignition problem - not if direct input of fuel through the carb/aircleaner works. Sounds far more like a vacuum leak, bad gas or fouled fuel filter.

Bottom line: we'd need more info to troubleshoot it from here, but the primary problem is a fuel problem, not a fire (AKA: ignition) problem, from your description.

Red Rider, thanks for the info.The leaking of air at the manifold sounds like a good possibility to explore. Just got n so we'll be on it first thing in morning . I get kind of scared hearing all these computers & shorting them out ..but I guess if I keep riding I have to learn to trust these new things. thank Rider, are you available thru the day, to reach you if need be?? I'm retired so all my time is all mine...lol I'm loosing some fine riding weather now so...gottomove it .. t/c jzpanthru...

Hey Red Rider, I snuck away & got some work on my bike done .changed O rings on manifold, but some how lost spark. Or should I say have weak spark as I held the plug & wire to check by turning it over? Modulator light pulses when turning over, so it's firing but not strong. Everything seems to be set right. Is the "RED" wire to be connected to the top or bottom of the coil or does it matter? frustrating!
Thanks Redrider

Hey, jzpanthru, I'll give ya whatever advice what I can, but I am no expert at long-distance troubleshooting on bikes I've never owned. Plus I have to ride, too! So here goes...

I rode a friend's shovelhead in '82 for one day, and not since, so I am even less familiar with that engine than I am an Evo (newer, but never owned one, either). I do know that your engine is old, and wires can be changed - and that without a manual, I've no idea what wire goes where anyway. By the way, other than you saying it is a shovel, you haven't given us much of a description - is it a particular Harley-Davidson model; i.e. FLH, FXR, etc, or describe by noun name like Electra Glide or Fat Bob? Or is it a Frankenstein, custom built ride?

If you don't have a service manual for your bike, GET ONE and read it a few times, at least about the things you feel you'd be able to work on.

As to it not sparking strong, how do you know?

Arrgh, the more I think about how to help ya, the more I questions I have. So here are more of those:

1. How long have you had this bike?
2. Have you ever seen it run? If so, when?
3. Why were you concerned about the ignition module?
4. Why did you replace the O-rings? Frankly, this confuses me a lot, as I can't think of an o-ring on either the intake or exhaust manifold, per se. Gaskets, yes, but not 0-rings on manifolds.
5. What carb is on the bike, a butterfly Zenith-Bendix or was it upgraded to a CV?

And these are just for starters. If you live in northern Nevada, I know just how to get you learning & riding on your bike, but it won't be easy through this forum. Frankly, you'd be best off taking the bike to an independent motorcycle shop that would be willing to get your bike up & running AND tell you all about what was wrong and what needed to be done.

One more tip: don't take anything else apart or replace anything until you know exactly what you are doing. It sounds like you may have added a new problem.

I really hope you get this scoot running and get her out rolling. Good luck & let us know how its going.

Thanks, Red I'll keep in touch...