Short, parasitic load, or bad battery?

After about a year of my 1981 Kawasaki KZ440 LTD sitting, the gas tank rusting, and the carburetors fouling, I was getting "down to the short rows" as far as getting it back running. I purchased and installed a new battery (fully charged), checked that the motor still turned over, and then covered the bike while I waited for my new petcock to arrive. Two days later, I installed the petcock, filled it with gas, turned the ignition on, pressed the start button, and then...... nothing. The neutral light wouldn't even turn on.

I checked the voltage of the battery, and it literally registered 0 volts. Here are a couple things I noticed that seemed off or strange to me:

1.) The neutral light will stay on even if the bike is in "lock" (Not sure if that's normal - the only way to turn it off is to put it in gear, which I did before covering it for the two days).
2.) When I check the resistance across the battery cables (with no battery installed), there is zero resistance. Wouldn't this mean the battery should spark like crazy when I hook up the two cables? It just seems unlikely to me that a short would develop over that two day period that would cause the battery to discharge all of its energy.

Any thoughts on what would cause the voltage to drop to zero in a battery over a two day period?

Austin

Is that with the ignition off and the key removed?
If yes, then I think you have short somewhere.

Do your resistance check from b+ to b- cables again with the battery removed-unplug your ignition switch and see if your ohmmeter goes open circuit. Bad ignition switch?

If your neutral light remains on with ignition key off, then effectively it's behaving the same as key being on. This indicates a problem with your ignition key. A question would be is anything else "live" too? Turn signals or brake light working? Knowing what else may be working when the neutral light is, to help isolate if the key switch is really the problem or if some wires have been shorted in the loom (probably near the new battery...).
Yes tho, the battery terminals should have sparked when hooking up battery IF something was drawing current via some random short.

Thanks for the responses. The neutral light may have been a red herring actually. I recall now that the previous owner had wired the high-beam switch to do exactly the same thing as turning the key to "On" - so the engine can start without the key as long as the high beams are on (coincidentally, this means the high beams don't work).

This also means the neutral light can stay on if the light switch is in the "high" position, and it is in neutral. I don't think this extra "high-beam functionality" would cause the short, as that was never a problem before - worst case is it would drain the battery until the voltage was too low to light the neutral bulb (probably about 6v?).

I just went out quickly and checked resistances while trying a couple different things:

1.) When the key is "On" (or the high beams on), there is no resistance (<1 Ohm) between battery cables.
2.) When the key is "Off" (and the high beams off), there is about 4 Ohms resistance between the battery cables.

I need to do some more testing, but now that my battery is at 0 volts, my battery tender won't charge it - and I don't want to keep experimenting with $45 batteries. Do you think jumping it is a safe option, or would that not be a good idea with the battery completely shot?

Thanks again,

Austin

NO - do not jump it with a bad battery,and whatever you decide to do NEVER jump it from a charger or from another vehicle whose engine is running as that can wreck the bike's electrical system.

If the current battery cannot be properly charged (charging MUST be done with a charger that puts out NO MORE than 2 amps) then replace the battery with a good one. Ed

This is a rather challenging issue since there has been some jiggery pokery with the electrical system, however, based upon what you have described with the headlamp's HI/LO switch; the PO has basically removed high beam function, in order to create a parallel ignition switch "ON" function:
Quote:
previous owner had wired the high-beam switch to do exactly the same thing as turning the key to "On"

Not coincidental, that the High beam no longer works because that switch function has been pirated to be an ignition key-on now. If I understand this correctly, then you no longer have a high beam at all, only low beam?. Or basically, the HI/LO switch's input 12vdc, output's to the ignition switch's "ON" terminal. (who knows really but this is my guess). Not sure how he got the 12vdc input to the light switch to remain live if the key is not present and ON first though?

Whatever. If having the High Beam switched on, is the same as ignition switch "ON", then your ignition system is live now and thus, I believe, you could very easily have a battery drain through your ignition circuit and any ancillary things like neutral light or even I would expect the tail light?
I guess it depends on exactly how the PO cross-wired the ignition key as to what is live if you forget to flip the high beam back to low beam.

Ultimately, you said this has never been a problem before so it stands to reason it's not now save for the forgetting about high beam cannot be left on.

At this point, I would want to remove that battery from the bike entirely and put it on the shop floor and [EDIT: using a regular car battery charger on LOW rate - is usually 2amps- , not a maintenance charger] trickle charge it for an hour or two to see if you can pull it back (lead acid battery assumed here). I'd leave my multimeter on the clips to watch the voltage and not rely upon a little charger's Green/Yellow/Red indicator. If the battery was brand new, it should be able to survive a drop to zero if it wasn't driven past to negative or into reversal (was the battery HOT when you discovered this issue?).

Another issue. Ohms law. If voltage drops, then amps go up. So whatever was draining the battery was experiencing higher amps as the voltage dropped below 12vdc. So you may find a few components were ... stress tested; depending on how exactly this by-pass switch was achieved.

The "LO" does turn the headlights on, "HI" is effectively an ignition key bypass. It's possible I always had it on "LO" because I would have had no reason to set it to "HI", as I've always had the key. Maybe that's why it was never an issue before.

Either way, I guess I just have to get the battery charged and hope it's as simple as making sure the light switch stays on "LO".

Then the next step would be fixing whatever the PO did to it.

Thanks for your feedback.

Austin

Yeah, hopefully all the PO's re-wire happened in the headlamp bucket & i suspect will look obvious.
That color wire diagram JPG/PDF will help a lot to I.D. what is different & where.

Out of curiosity:
Headlamp at LO. Key to ON. Low beam good?
Headlamp at HI. Key to OFF. Low beam no good?

I suspect it will be this way for the simplest method to have done that hi/lo/key hack but just curious...
Good luck!