1988 sportster
1250 conversion
My bike has been a real bastard this year.

The problem I am having now is the bike completly loses electrical power momentarily and dies. I was able to get it home last night.

Here are the things that have been replaced in the last 2 weeks
-battery cables
-voltage regulator
-ignition module
-battery
By a mechanic

The ignition switch and handle bar switch in march.

I have tested the
-Stator
-battery charge
-ground for voltage regulator
They are all good and well within specs.

Havent checked the coil resistance yet.

So what could possibly be wrong that the bike completly loses power?

 

Deleted post

 

It sounds like you've pretty well covered the usual stuff, and then some.

If you are really "completely" loosing power (everything is dead), the possible causes should be a short list of 2 locations.

1 - Between the negative battery terminal and the frame. That's the negative battery cable and its connections.

2 - Between the positive battery terminal and the fuse block/circuit breaker/relay panel.

If your ground cable attaches to a stud on top of the tranny, you might want to remove the stud, clean up the threads and reinstall. These have been known to corrode and create a bad ground point.

 

If the bike loses all electrical power, the problem is somewhere between the battery and the ignition switch.

The mechanic that is troubleshooting by changing parts is clueless as to how the electrical system on this bike works.

If changing these parts was his idea and suggestion, you should tell him you want your old parts and money back.

Here is what should have been done first:

Check integrity of all battery cables and connections to make sure they are clean and secure.

Check the integrity of the red wire that connects the battery to the main breaker.

Check the integrity of the red wire that goes from the main breaker to the ignition switch.

Replace the main breaker (this ten dollar part is probably the problem).

Don`t touch the coil.

Fire your so called mechanic.

 

Battery cables are new all ***** cables. Cables are tight. The big question is. Is the cable making a good ground to the stud where it attaches to the frame.

The other question is the Key ignition. It is drag specialties China special. Just because it is newer doesnt mean it's good.

If the Ignition Coil is bad could that shut down all electrica;l power?
What about an intermittent ground on the new Voltage Regulator? Would that shut down all the power?

Can I for trouble shooting purposes connect a secondary ground cable from the top of the battery to someplace else on the frame?

 

The reason for the new voltage regulator was a faulty one that threw a voltage spike that took out the twin tec ignition.
I had the bike running and jiggled the wires to the ignition switch and it didnt kill the bike. The main breaker was replaced as well because the voltage spike fried it.

 

No, a bad coil won't kill things like lights and indicators, and a bad ground on the VR will only result in the battery not getting recharged.

Yes, but unless it's the size (gauge) of a battery cable, don't try turning the starter with it. If you can catch it when everything is dead, a #10 or #12 wire could be used as a temp. ground wire to check and see if with it, the lights come on.

You could also temporarily connect a toggle switch across the ignition switch wires, and use it when the bike dies to see if that brings power back. If it does, the ignition switch is bad.

 

Thanks.
I'll use one of the old cables. Run it from top of battery to engine mount.
If that doesn't work I'll try a new ignition switch.
I just replaced main 30 amp. For the one that was in there as well

 

Thank you.
I think the issue is resolved. At least I hope so. It was either the 30 amp main or the ground cable.

The 30 amp main I replaced with a 30 amp I had sitting around.
The ground cable I left in place and ran another one from the top of the battery up under the tank all the way to the tank mounting bolt.

I think the stud is corroded as you mentioned and even a new cable wont work well on it.

When i tear down the oil tank and tins this winter I will get in there and wire brush it to make sure I have a good electrical contact area.

Thank you and the other posters for narrowing this down for me

 

I was going to suggest changing out your main breaker, they're cheap and worth a shot. Hope that was part the problem. My 1991 had a recall on the main breaker soon after I purchased it. Of course, it worked fine until I got the recall notice, then it started to crap out. Go figure.

You have had one hell of a year with your bike, my friend. I've followed your travails over on xlf.

Hopefully, Santa will be real nice to you, and 2015 even better.

John