Electrical Questions...

Hey folks:

2 electrical questions...

1: My battery is not charging. Where do I start with the troubleshooting.

2: I can never get the bike started with the kicker when the battery's dead. Is that normal?

Thanks,
-Kit

your problems have the same root. it won't start with a dead battery if your cahrging system is faulty, or if your battery is like, TOTALLY discharged.
sounds like you have either an alternator or rectifier prob. and to check is kinda wierd.
you can put your dc voltmeter between the white wire of the rectifier off the + battery lead, and ground, then temp. disconnect and put together the brown and green leads from your voltage regulator, you should get like 14 volts. don't rev the bike when doing this.
if you get good voltage this way you know that the rectifier or alternator is bad. i'm refering to a clymer manual, hope this helps, let me know what happens. on these checks it says to make sure your battery is near full charge, kinda ironic right? why would we be doing this if our battery was at full charge?

First thing I do when a bike isn't charging, is to ensure the wires coming off the stator and connecting to the rectifier are snug and not corroded. I also check the main battery wires as well... make sure the wire to the starter solenoid and engine ground are tight and clean. This is the MAIN cause of charging issues.

Next step to insure the battery is capable of holding a charge. If a cell goes dead, the battery won't stay charged. Buy a small and cheap hydometer and check the cells. They cost about $3 at an autoparts store. These gizmos include instructions on how to perform the check on each cells. If you find a bad cell, replace the battery.

Next step would be to start troubleshooting the stator or rectifier. If there is insufficient AC being generated out of the stator, then a new stator is needed. If the stator is working, it plugs into the rectifier and this turns the AC to DC then passes it to the regulator for voltage level control... then to the battery for storage and distribution. An easy first step is to measure the battery voltage. After charging on a trickle charger, start the bike and at idle there should be about 13-14 VDC. Rev the engine and you should have about 15.5 VDC... If you have too much voltage... the rectifier is bad and if you have too low, you should look more at the stator output. Have pity on me if I got the regulator/rectifier functions backwards as I always get those two gizmos confused as far as their names go...

Anyway, once you have a sense of what is wrong using some good troubleshooting, you can make measurements using a manual to ensure you are not replacing something that doesn't need replaced. Last piece of advice is to be leery about eBay electrical gizmos... all the auctions will say either "no idea of condition" which means the thing is junk or "came off running bike" which means you have about a one chance in five that it might work... hehe (sorry, getting jaded about eBay electrical stuff!)

You got the rect/reg functions correct, George.

As a thought, I think 15.5V would be a bit high. Generally, if the charging voltage is over 14.5V then the electrolite will boil out. Nominally, I would expect the charging voltage to range around 13.5V to 14.2V.

It's quite possible for the rectifier/regulator module to fail in such a way that it won't charge the battery and will instead discharge it.

Another battery test is to give it a charge on the bench and let it set for several days. After several days of sitting idle it should still measure around 12.5V, maybe a bit less but more than 12V. It's quite possible for the battery to have a shorted cell that will discharge it and prevent it from maintaining a charge.

- Nate >>

Urgh.

Thanks for the tips, guys.

I looked at the Clymer, but I can't do the tests. The white wire is crimped to the battery + cable. I managed to follow it & find a disconnect in the middle, but the electrics don't turn on at all when all the stuff that's supposed to be disconnected is disconnected. (There is no 6-connector block on the left, but there is one on the right, so I disconnected that. While disconnecting the 9-pin block in the headlight shell, I saw a bunch of disconnected wires. Since all the lights work, I don't know what those wires are for.)

At idle, the battery terminals read 13-14 VDC. This creeps up slowly when revved to 3-4k, then falls again. (The voltage jumps around a lot.)

The battery seems good. It was new in December or so, held its charge for quite a while 'til it went dead from many starts. Recharged it, same thing. Recharged it last night, & it had no problem cranking the engine over today.

As it turns out, I hadn't really looked closely enough at the big-box-o'-spares a certain kindly member here just sent me: both reg & rect were hiding in there! I will now blindly swap them out & see if it helps!

Cheers,
-Kit

Didn't manage to get 'em switched out before dark, but I noticed that I was confused about what the rectifier is. I thought it was the cylindrical thing the + cable from the battery goes to, but it's not.

The rectifier Wireman sent me is a flat metal thing covered in a beige plastic coating. (Mostly, it's a little flaked off on one side. It looks like the one in the Kawasaki parts diagram.

The thing on the bike that's plugged in where the rectifier should be is a black thing with a big heatsink on it. It does not look much like the one Wireman sent or the one in the Kawi diagram.

The plot thickens...

-Kit

Well, I got the regulator & rectifier replaced today, & got the tests from Clymer done as well. The voltage levels at the battery don't jump around as much now, but it looks like the stator's toast. I got about 0.5 VDC between the rectifier's white wire & ground (14 VDC or higher is good) & resistance between stator wires is 0.8-0.9 Ohms when it should be between 0.4-0.6 Ohms. I don't suppose there's any way to repair a stator, is there?

-Kit

i think the parts i sent were from a 74 kz400.does anyone know if the statter will work also?i still have motor.

KitNYC wrote:

... I don't suppose there's any way to repair a stator, is there?

-Kit

I have used these guys in the past to repair/rebuild a stator, and they did a great job at a reasonable price:

R.M Moto Électronique

...just drop 'em a line, they respond pretty quick. They did mine a couple years ago for just over $100 (US) and I got it back in a week...

I emailed them a few months ago when their website changed and asked if they still do stator rebuilds, and they said yes...

Post edited by: biquetoast, at: 2006/04/01 22:41

Hi Kit,
I'm a little confused by your test results. The white whire should have had at least 11 volts if the wire is connected, and the ignition switch is on.

Also, those readings on your stator could just be off due to your meter being out of calibration or some dirty contacts.

I wouldn't jump to the conclusion that your stator is bad based on those two tests.

Can you give a few more details on your tests? I'd hate to see you spend unnecessary $$$$$$$$$$$$$$$.

The 76 KZ 400 charging system is very complex and requires quite a few tests to fully analyze the problem.

Post edited by: loudhvx, at: 2006/04/02 01:35

Bt: Thanks for the tip. I'll keep them in mind if I ever have $ again.

Lou: Hey, I was hoping to hear from you on this! Getting .4-.5 VDC when 14 was the threshold seemed pretty fishy to me as well.

I was tearing my place apart trying to find the multimeter I usually keep in my backpack. I finally found it at the bottom of a box of unrelated stuff, put it down somewhere, picked it up from the table next to the couch, then went outside to do the tests. Sat on the bike, & realized that I had 1 multimeter in my hand & 1 in my back pocket. At this point, I don't remember if I double-checked the resistance readings off the stator with both or not, but I know I read voltage off the white wire with both meters & they agreed. The black rectifier that was on there when I got it was around .44 VDC & the grey one I swapped in was around .5 VDC.

For the tests, I basically followed the Clymer. The Clymer mentions some stuff under the left cover that's not there, but there's stuff under the right cover that fits the description.

First test, I disconnected the 6-pin connector under the right side cover & the 9-pin connector in the headlight, then disconnected the white wire from the rectifier where it plugs into the battery +. I then pulled green & brown wires from the regulator & stuck a thin piece of metal between the connectors on both wires & started the engine. I connected the + lead from the multimeter to the white wire coming off the rectifier & touched the - lead of the multimeter to about 73 different parts of the frame, assuming that the extremely low reading was due to a bad ground. Bad ground gave a reading very near zero, good ground gave a reading between .4-.5 volts. Lacking access to 1-ohm, 200-watt variable resistor, I skipped the rest of that test & proceeded to check resistance between the yellow wires coming from the alternator.

Did I just do the test wrong?

Any idea whether the '74 stator would work?

I'd hate to see me spend any unnecessary $$$$$$ either.

Thanks,
-Kit

That test will test the alternator's field coil and stator, along with the rectifier and associated wiring all at the same time. That means you still have a lot of tests to run before you can tell what's wrong.

That test basically is just bypassing the regulator by jumping the brown wire to the green wire. This means the alternator's field coil is getting full battery power to create a magnetic field. This means the stator is putting out full power to the rectifier. The white wire must be disconnected or the excessive voltage will burn out the bike's wiring. Under those conditions, the white wire should have had a very high DC voltage on it.

First lets make sure the battery ground is connected to engine and frame. Measure the resistance from the battery negative post to the frame and then to the engine. It should be nearly zero ohms. From now on we will use the battery's negative post as ground.

Next we need to verify the field coil is good. Measure the resistance from the green wire to ground.
I'd expect around 2 to 6 ohms.

Next connect the regulator's green and brown wires as in the Clymer test. There should be 11 to 12 volts on that little jumper when the ignition switch is turned on. (meter negative is on battery negative)

Just for kicks, place a screwdriver near the alternator cover and see if it gets pulled by the field coil's magnetism when the ignition is switched on. If it doesn't, don't worry, the magnetism may be focused inward toward the rotor. I haven't tried it so I was just curious if the magnetism would radiate outward.

After these tests there are still a few more.