Charging @ 21 volts & what year?

I bought a 79 KZ650B3 Last Friday. It has fried the battery and virtually every light bulb on the bike. I got it looked at this morning, and my mechanic says it's putting out 21 volts, and the regulator/rectifier needs to be replaced.

He says it's an '80 model, that the build date stamped on it is 12/79. The title lists it as a '79 model, with a sale date of 3/25/80. The serial number is KZ650B532898.

I've looked online, and there are different regulators/rectifiers listed for a '79 and an '80 model. How do I figure out which is which?

Also, what is the best source for one?

Go to www.buykawasaki.com click on owner info then parts diagrams then continue for motorcycles, enter you serial number in the box and it will give you the info.
Ride Safe
Well scrap that idea, it doesn't work for anything older than 1986 models


Post edited by: The Milkman, at: 2007/07/24 12:27

Thanks for the help, but, it doesn't work for a bike that old.

Post edited by: seanof30306, at: 2007/07/24 12:32

Sounds like you've got a late build 79 that wasn't sold until 80. If memory serves me correctly, they didn't sell the B model in 80. The B1 was 76/77, the B2 was 78 and the B3 was 79. If I was you, I'd go with the reg/rec for the 79 (although I didn't think they changed much between 79 and 80 so I would think that either one would work...I didn't think anything really changed until 81 when they switched over to electronic ignition).

Also, with that many volts being pumped through and enough generated to pop all the bulbs you probably should give your wiring a good thorough once over to make sure you didn't fry any wires or melt any connections. (Been there, done that).

Sound like a B2.
The B2 frame # started with kz650B-508016.
The B2 had all capital letters KAWASAKI on the tank.
While the B3 had lower case Kawasaki.
The B3 frame # started with KZ650B-046201 and came from Japan.
B2's were assembled in Lincoln, NE.


Hmmmmm, that is preplexing!


Go to buykawasaki.com
On the left, click on OWNER INFO.
On the next page on the far right hand side click PARTS DIAGRAMS.
The click the CONTINUE button next to the box that says motorcycle.
Then simply enter your year and CC's and leave the other field set to all and it will pull up your parts diagram.
I hope that helps.

I don't think there was a 1980 650 B model. It's probably a 1979 sold in 1980.

If your regulator/rectifier has 5 wires, and one is a brown wire, then it's a 1980 model reg/rec.

If it only has 4 wires, it's a 1979.

The 1980's extra brown wire just goes to a switched 12v source to sense the battery voltage while the ignition is on.

The 1979 reg/rec senses it's output wire and so eliminates the extra wire.

You could use either reg/rec, but the plugs would be different, and you would have to wire an extra wire in.

Post edited by: loudhvx, at: 2007/07/24 13:00

Yea it's a 1979 B3 by the serial number, which was the last 650B at least in the USA. I think it more likely you had a bad battery first providing no load letting the charging system run wild. I had the same thing happen when the negative terminal broke off a battery on one of my 650s years ago. Burn't every bulb on the bike out. Wasn't a charging system problem at all. Lou will correct me, I'm sure, if I'm wrong, but I think it near impossible for a charging system no matter how goofed up to provide 21v to a good 12v battery as the battery would not possibly let the voltage rise that high.

well, you'd probably have to rev it pretty hard, but I think you could force 20v on a battery. I'm pretty sure I did that as a test 10 or 15 years ago.

But Ron has a good point, make sure all the battery connections and related connections are good before buying a new reg/rec.

Well, so far, so good.

77Davo650 turned me on to a great place here in Tulsa called Ron's Cycle. They have a TON of used parts and parts bikes, and seem to specialize in Kawasakis.

I got a regulator from an 80 model. As loudvhx said, all I had to do was hook the brown wire up to switched power. Put a new battery in it, looked the wiring over and checked grounds, and it started right up. It's charging at about 13.3 volts, and idles perfectly (it wouldn't idle at all before). Also, the "neutral" and "high beam" lights work again, but the "brake" light doesn't.

I need to pick up a brake light switch and a headlight tomorrow. I've also got to figure out what's going on with the blinkers. None of them work at all; neither do the indicator lights on the panel. I'd think if the flaser was bad, they'd at least light up, but not flash. Is that correct?

Did you replace all these bulbs? If not with 20+ volts they are all bad. I burned the headlight, tail, all the indicators, all 4 blinkers before I knew I had a problem.

So far, I've replaced the tail light and two blinker lights (there are only two blinkers on the bike). I also have to replace the headlight.

The "neutral", "high beam", and "oil" lights in the gauge cluster are working. The "brake" light, turn indicator lights and gauge illumination lights aren't working. I'll look at them tomorrow.

By the way, what's the best idea for a replacement headlight? The parts store and Wal-Mart didn't have it, and I'm looking at one on ebay express for 60 bucks! It's NOS, but, that still seems a little steep.

How about a halogen lamp?

Also, is there a place I can send the gauges off to be reworked?