Strange Batter drain.

I have a 1983 KZ750 Spetre that will drain the battery at random times. I could drive it months with no problem, then one morning the battery will be completly dead. It may drain it again the next night, or taunt me for a few more days or months before draining it again.

The batter is brand new, and the system charges very well.

I am faily good with a multimeter and can check thing out, if i have a guide to work with. But I dont know where to begin. I have a feeling its a relay that is not disengagine, but im not sure.

Any help would be appreciated.

Do you have anything extra hooked up, like fairing lights, radio, alarm system, or any mods to the electrical system, like the coils with a relay?

A circuit malfunction may exist and be drawing current all of the time.
What is the general condition of the wire harness connections?
How about checking the connection to the regulator/rectifier, my bike had a problem with the battery & charging system, it turned out to be corroded connections at this point.

Maybe your ignition switch is old and not shutting off some circuit.

Post edited by: OKC_Kent, at: 2006/03/01 15:26

Can only think of three things. First can be checked by putting your hand on a coil next time this happens. If the coil is warm, you have a connection in your ignition switch that is allowing the bike to actually stay turned on when you shut off the key. The second thing is a bad cell in your battery. A multimeter won't help. You need an inexpensive hydrometer (battery fluid tester). They are about $2 at an autoparts store; get the smallest you can find. It will come with a little hose. Put the hose in each cell and test the cells. There will be instructions on the container the hydrometer came in. A dead cell can be shorting and discharging your battery and the short may be intermittent. Last may be a loose wire somewhere such a battery wire. Check your ground to ensure it is clean and tight at both ends of the wire and also the hot wire to the starter solenoid. I would also clean the contacts from your alternator to your regulator/rectifier and I would coat all these connections with dielectic grease.

Post edited by: wiredgeorge, at: 2006/03/01 15:39

There are no added mods to the bike, its all factory. In a million pieces at the moment , but all factory. No fairing or radio, no extra lights or fancy gadgets.

The harness has some age to it, but overall the insulation of the wires are not dry rotted. Still flexible. The ignition switch is a bit on the loose side, but the gauge lights power off with the keys without any trouble. Is there a way to meter the switch to tell if it is shutting off correctly?

I will try the warm coil idea this weekend. I should be able to hookup that part of the system to trouble shoot it.

The regulator/rectifier would only hurt the charging system would'nt it? Before I pulled the engine off this week, I checked the charging system and it was charging 2 volts above the reading from when the engine was not running. I am understanding this is a good thing.

The battery is new, but I have access to a hydrometer. Just because its new does'nt mean its not broke. hehe been there before.

Just a note though... when I would ride the bike the battery was being charged and held it very well. It only dies randomly when sitting overnight.

I know this is too obvious, but you know that one of the "off" positions on the ignition switch leaves the tail light on as a parking light, right?

Just trying to cover the simple stuff first.

loudhvx wrote:

I know this is too obvious, but you know that one of the "off" positions on the ignition switch leaves the tail light on as a parking light, right?

Just trying to cover the simple stuff first.

Is that only specific to his model bike? I've never noticed that on my Z1.

Actually, I'm not sure it's on his bike specifically, but it's on all of the early 80's KZ's that I've seen (that I can recall).

I have never noticed the taillight on, but I will double check the switch to see if it has a position like that. I almost certain its in the off position though.

I've done that. Turned the key to the right and removed it leaving the tail light on overnight and drained the battery.
Doh!!!!!!!!!

........................................................................................
Woodstock ON Canada
1980 kz750E1, 4->1, K&N pods

78 KZ650C2 has that function too, I believe the 77 does as well. Wayne

OH YES the 77 kz650 b1 has that odd option on it also learned the hard way and left the tail light on to come back the next day to a dead battery :blush:

Some municipalities (like the one where I grew up) require parking lights on a vehicle if it's parked on the street at night. Lot of dead batteries there.