78XS rehab

[Bax]

Concerning from previous pic you posted.

[Eab]

Concerning from previous pic you posted.

I hadn't pulled that ground when I'd done over the battery tray but I'll definitely check it out again. I was a bit firm when I was wrangling the new fuse block in place, wondering if that resulted in a few broken strands of 40 year old wiring. Should be able to get a few hours in tonight, I'll let yall know how it goes. Thanks again for the suggestions!

[jetmechmarty]

I hadn't pulled that ground when I'd done over the battery tray but I'll definitely check it out again. I was a bit firm when I was wrangling the new fuse block in place, wondering if that resulted in a few broken strands of 40 year old wiring. Should be able to get a few hours in tonight, I'll let yall know how it goes. Thanks again for the suggestions!

I've seen more than a few poorly made crimps on replacement fuse boxes. Not that it's your starter issue, but can create lots of issues. I'm not suggesting shoddy work here because I know nothing of the OP skill level.

[Eab]

Possibly related symptoms: turn signals don't flash. Both front signal lights stay on when the key switch is on, rear signals are currently not connected. Brake light switch is behaving oddly. Also, the light on/off switch at the right handlebar only turns on/off the headlight - it seems like it should probably turn off more?

Anyway I'm betting someone with more than like two months of moto wrenching will look at these symptoms and say "well of course this is the problem you fool", except you guys seem nice enough to just think the second part.

I've pulled the fuse block and tugged on the crimp points a bit and nothing seems loose. Also, I pulled the plugs and ran the starter and the motor moves the pistons just fine with the plugs out. Checked for spark on a plug when I had it out and that looks OK too, in case that rules some things out.

It seems like the battery gets drained Fast on these attempts. 2 month old battery, charged fully overnight and the strength of the starting attempts seems to suck it dry pretty dang fast.

[Bax]

Hi Eab, All sounds like a bad ground to me. Three things to try with your recent maintenance. 1. Is the battery polarity correct? 2. Key off, no expected current draw, pull the main fuse and check for current across the fuse holder, if yes then you have a short to ground (may explain the battery drain). 3. Jump the negative terminal to the engine block and see if the issues clear.

Bax

[MaximPhil]

Hi Eab,
Only 78's have the headlight on off switch so that is all it does. Later models have the delayed headlight coming on only once engine is running. Always ride with it on as it makes you more visible to the brain dead cage drivers. Mandated in most states.

Phil

[Eab]

2. Key off, no expected current draw, pull the main fuse and check for current across the fuse holder, if yes then you have a short to ground (may explain the battery drain). 3. Jump the negative terminal to the engine block and see if the issues clear.

Bax

Looking like it's #2. Got .3ish volts moving across the main with the switch set to off. I tried straight from the block negative terminal to the engine block (with the standard batt-to-ground in place) and it doesn't seem to behave differently on the start attempts. I guess I'm going hunting for a short to ground, from what I hear sparks and smells are helpful to look for, but I'll take any tips on isolating the location of the short, if anyone's got any wisdom

[motoman]

Eab,, possibly ignition switch contacts crudded up internally. Un-plug and remove ignition switch and spray a good dose of electrical cleaner in bottom side till it runs out clean. That way it'll save from having to seperate cyl. assembly from housing for cleaning contacts.

[Bax]

Eab, electrical isolation for the next steps. Same condition for key off test, measure for current across the main fuse and then start pulling the box fuses one at a time until you get a change in the measured current draw across the main. Should be able to narrow down where to look.


---Bax

[Eab]

Eab,, possibly ignition switch contacts crudded up internally. Un-plug and remove ignition switch and spray a good dose of electrical cleaner in bottom side till it runs out clean. That way it'll save from having to seperate cyl. assembly from housing for cleaning contacts.

Do you suppose the ignition switch contacts being crudded might cause the current flow across the main fuse when the key is off? I don't think crud would cause a short to ground (as Bax suggested) but I also don't have 8,000+ posts and 15 years under my belt. I want to try to minimize unneeded fiddling to avoid adding to my troubles.

Also: I am assuming having the rear blinkers disconnected wouldn't impact this problem, but I'd come across another thread where someone was having elec issues and had their turn signals off, too, so I want to cover the bases re: my potential ignorance

[DiverRay]

Eab, try what Bax just suggested, pull the fused one at a time. If it's the ignition switch, you should go to 0.0V with the ignition fuse pulled.

[Eab]

Gave it a shot: .5 volts across the main no matter which fuse was pulled. I'd been noticing some powder coming from the battery's negative cable's housing and it seemed a bit brittle. I bit the bullet and slit the sheathing and there's significant corrosion on one end, not sure if it's enough to cause the issue. Don't have a spare or a decent makeshift on hand to try one now, going to figure something out tomorrow. It doesn't really look significant enough, and that one rough-looking end is actually smoothed/cleaned up, not a great picture.

[jetmechmarty]

Gave it a shot: .5 volts across the main no matter which fuse was pulled. I'd been noticing some powder coming from the battery's negative cable's housing and it seemed a bit brittle. I bit the bullet and slit the sheathing and there's significant corrosion on one end, not sure if it's enough to cause the issue. Don't have a spare or a decent makeshift on hand to try one now, going to figure something out tomorrow. It doesn't really look significant enough, and that one rough-looking end is actually smoothed/cleaned up, not a great picture.

You need to replace that ground cable. Try JP Cycles. There has to be a nice Harley-Davidson cable close enough in length to work better than new. If you're handy, you can make it yourself.

[Eab]

Any guesses as to what the deal is with this switch and fuse? I can't find it on my wiring diagram, and the three-position toggle doesn't seem to do anything. There was one lead connecting to the accessory port, beats me what it does though. When I pull the fuse, things don't seem to behave differently in their current not quite running state. Also: if I'm not using the accessory port, is it OK to just remove it? I wouldn't hate taking one more variable out of the equation.

[bikerphil]

It's not factory, someone added both of those for some kind of accessory.