Testing Rectifier & Magnetic Switch

Can anyone tell me if it is possible to test a rectifier and a magnetic switch from a Kawasaki Z 900 if it is off the bike. Any help would be helpful. Thanks

With the rectifier from your Z900 off the bike, you can check it with a multimeter or ohmmeter. Put the meter in Ohms scale or R scale at X1 or X10 scale.

The plug should have a white wire, a black wire and two yellow wires if memory serves. You will first measure across the white and yellow and then the black and yellow.

First the white/yellow test. Put your POS lead on the white and the NEG lead on the yellow. Note the value for that white/yellow pair. Reverse the probes from your meter and remeasure. Note the value. One value should have VERY low resistance and the other should have a value AT LEAST 10 times greater. Do this for the white and second yellow wire as well. You should have similar results.

Now, instead of the white/yellow pairs, use the black wire and measure black and yellow wires. Do both and reverse the probes in the same way.

In all, I think there are a dozen measurements if you do all the combinations. If you find that the resistance is either low or high in BOTH directions in doing the tests, replace the rectifier bridge.

Since you listed the bike as a Z900, you are likely outside the US. I am not sure what part you refer to when you asked about the "magnetic switch". Are you asking about the starter solenoid (relay)?

WiredGeorge it is a Kawasaki Z1 900 and it is the starter solenoid I think it is the same as a magnetic switch. Thanks for your help. Steve

Post edited by: Z Parts, at: 2007/02/27 19:04

To test the starter solenoid, I prefer to do it while it is in the bike. If it is off the bike, all the solenoid does is close a switch. Get a bulb holder that holds a 12V bulb.

This gets complicated sounding so here is the only way I can think of to test....

Use some smaller gauge wire; perhaps 18ga. Connect bulb holder metal shell to the NEG battery terminal with a wire.

Connect the battery POS terminal to the solenoid where the battery normally connects with a wire.

On the other side of the solenoid (other large lug) where the starter cable connects, connect a wire to the bulb holder POSITIVE wire.

Last, take yet another piece of wire and touch the POS battery terminal and the solenoid connection where the black wire from the right switch gear starter button is soldered. When you do this, you should hear a CLICK where the relay closes the connection and the light should come on. You could probably use any 12V DC battery to do this test. I am pretty sure that someone smarter could probably come up with some way to test that was less tedious bwhahaha

Z Parts wrote:

WiredGeorge it is a Kawasaki Z1 900 and it is the starter solenoid I think it is the same as a magnetic switch. Thanks for your help. Steve<br><br>Post edited by: Z Parts, at: 2007/02/27 19:04

Hi ZParts, welcome to the forum.
If George is not goina' whoop me one, I think I may be able to offer some guidance, provided you have a friend to hold in the clutch and press the start button while you check voltages.
Remove whatever is necessary such that you can easily get to your solenoid and battery posts. Now set your voltmeter to measure DC volts and select any range appropriate to measure twelve volts. Turn ignition on, and hold the negative(black) test lead on the negative battery post and the positive test lead(red) on the "battery-side" terminal of the starter solenoid. This will be one of two large terminals with a wire, probably red, that runs, more than likely directly to the battery positive post.
What do you read when the start button is pushed? Hopefully around twelve volts. Leave the black test lead on the negative post but move your positive test lead to the other of the large solenoid terminals and press the start button again. What do you read?
If everything is good, you will read your battery voltage, more or less, on both solenoid posts. If you do, then the problem is towards the starter; either a connection or the starter itself.
Your starter motor requires or "runs" on 12Vdc, so you must have basically that voltage on the solenoid terminal that connects to the starter. By checking the voltage on both sides of the solenoid as suggested, you have tested both the solenoid function and the battery/clamp integrity at the same time.
If you do not get twelve volts on the solenoid terminal leading to the starter, then make sure your ignition switch and kill switch are in working order. I can help with that too if necessary.

The reason I answered this fella as I did was he said the solenoid was off the bike. I wouldn't test the same way if it was on the bike, obviously.

Hey guys,
how do i by pass the kill switch on a 1975 z1 900?Do you guys know if there is a clutch switch on this bike?
1975 z1 900
1980 kz 750
1975 cb 360
1994 fxdl 1340
MIKE