Power Cut off

[hudson]

Hey gents- I was riding my 75/5 today and it cut out dead suddenly, like if I ran out of gas and need to flip petcocks to reserve. Which I did with no effect. It cut off and coasted to a stop. Hitting ignition button had no effect. No clicks, sounds - nothing. No lights, at all- low, hi, TS, idiot dash bulbs. Dead as a door nail.

Earlier The bike started right up, everything worked- rode so nice all the way up to the power loss- there wasn’t any erratic behavior even when that happened.

I had some friends bring a truck and I took it home. Thinking the battery and/alternator, I checked and it had 13+ volts. I assume this is telling me the battery and alternator are good since the battery is fully charged. Wouldn’t think it would be the starter as that doesn’t come into play when riding.

Scratching my head on this.

Alternator- enduro last 450
Boyer ignition
West Co Battery - approx 1-2 years old

The only thing I did is change the H4 bulb yesterday and it was a 55/60 Phillips- supposedly a little brighter. Could something have come loose in the headlight shell that would cause the total sudden power loss with no symptoms?

Thanks for any help you can give,

[Kurt in S.A.]

Starter relay acting up? That's not in the headlight shell, but that's the first thing that came to me. But they say, go back to the last thing you were doing.

Kurt in S.A.

[Seth]

What year /5?
Later ones had fuses.

[Zombie Master]

Got strong spark?

Electronic ignitions require a certain amount of amperage to work. You can have full volts, and not have enough amps to run.

Fact that you changed bulb, and were messing around, is suspect.

Check fuses.

[daz]

Early /5s had NO fuses. What year?

[Rob Frankham]

The answer... or at least the vicinity of the answer... is in your post. If everything dies suddenly, there is a break in the power feed to the bike. This could be either the positive feed or the ground...

1. Check the battery terminals for tightness.
2. Check the bike end of the main engine earth lead for tightness (bolt at the gearbox... DO NOT overtighten).
3. check the connection at the starter relay, the two red wires, make sure there is battery voltage at that point. Test this with the ignition switch on and off.
4. Check the red wire where it connects to the ignition switch for battery voltage. Test this with the ignition switch on and off.
5. Check the condition of the ignition switch. Do you get power to the bike circuits (green wire) when it is on? Do you get power to the lighting circuits (grey wire) when the lights are turned on?
6. Check the connections to the main bike circuit earth lead on one of the coil mountings under the tank. Check this point for continuity to battery negative

This should tell you where the problem originates.

Rob

[hudson]

It's a 1971. There are no fuses, the PO changed a little with the wiring, so it doesn't have the board in the headlight shell. There is a plastic electrical terminal connecting wires connecting several wires, otherwise it is individual wires connected to each other directly. But all is good as far as how it is hooked up. Has ran great and I inspected and redone the connections last year carefully and reconnected everything as is. No problems since for all this time. So it is wired correctly in it's one "custom way".

I can't test the for spark as when I turn on ignition, it is dead with no turn over whatsoever (unless there is another way).

I checked battery positive and negative connections including grounding wire to gear box.

I will look into the starter relay and ignition as you mentioned. Thanks so much for the input everyone!

[Tom H Ca]

I would start by pulling the headlight back out and see if you knocked a wire loose. Just remove the light and see if you get power back, could be a short. Or again, a wire may have come loose. Then move on to the other ideas.

Good luck,
Tom

[Rob Frankham]

I can't test the for spark as when I turn on ignition, it is dead with no turn over whatsoever (unless there is another way).

There are other ways of testing the ignition components but, at this stage, I would say it's a waste of time. The fact that nothing works suggests, pretty conclusively, that the fault is in the main routing from and to the battery. I say 'the fault', perhaps I should say 'one fault' it is capital mistake to assume that there is only one fault. Be that as it may, the main fault will almost certainly lie in the wiring to the ignition switch or in the ground wiring. Once you get that sorted, the ignition will probably be sorted as well, if it is still a problem, work on that.

Rob

[hudson]

I was fortunate enough to have a spare starter relay, but still a no go. And did some of the other tips mentioned. Thinking about what Rob said- since no voltage was getting to the ignition switch, I traced it back to the main power and yes, there was a grounding issue. The good news is that there was not too much that needed to sorted since the majority of the circuit is post ignition switch. Fixed and I put a new battery in just in case since I am leaving for a trip next week. I have to get some long rides beforehand just to get my "confidence" back that all is completely well. Sometimes getting your confidence back in your bike in fear of getting stranded- that's the hardest part! LOL!

Thanks to this group for always helping out!