So, on my 89 Softail I was riding home and it started acting funky. The power would die down, as if running out of gas, then power back up, then bog down, back up, etc. at an even rate (down up down up down up). It died at a stop sign. I checked the gas, some is in there but it's low (perhaps level at the petcock), and it started back up and got me home but had that same off-on off-on for about one mile all the way home. Of course I'll start by topping off the tank but it seemed weird that, although it did feel like a fuel issue, it would come back, then bog, then back, like a see-saw at an even rate, or "beat". Does this sound like anything to anyone? Ignition? Wires?
I'm handy at wrenching off and on parts but terrible at the diagnostic stuff. Many thanks.

 

Oh, this bike is heavily modified, been bobbed, I've had it for a few years and have had no problems like this before. Ususally runs like a beast.

 

Two quick cheap things to check. The petcock screen and plug wires. The petcock screen is always a good maintenance check to clean her out. For the wires you can sometimes see them putting on a light show when it is dark out and the bike is running. This is a good indication something is wrong. Or start it up and grab a hold of them. If you get a good ride then change your wires

 

Good advice. Will remove petcock and check screen, and then hold wires while standing naked in a puddle of water. Or, maybe just replace those wires.
Does this condition sound like an ignition going out?

 

Plug wire problems almost feel like you are going to dump the bike or someone rear ended you. They are very sudden. I have never had an ignition problem so I cannot comment. I would rule the cheap stuff out first.

I noticed it was my plug wires when I reached down to hit reserve. Felt like a bee sting. I smiled because I found the problem.

 

Let us know how that works for you. LOL

 

A partially plugged fuel tank vent can cause these problems along with a failing vacuum fuel petcock or a slight vacuum leak in the hoses going to the petcock. Of course a failing ignition module can do more things than we could mention here. Hope this helps

 

Don't think it's a vacuum leak - I only have one hose going straight to the carb. No vent either.

 

I had similar problem some time ago. Loose positive wire at battery terminal.

Might be faulty circuit breaker, loose wires somewhere etc. Or fuel related problem.

 

All fuel tanks are vented. Some have a vent hose, some have a vented cap. Check and see if the veny in the cap is functioning as it should.