TOPIC:

Situation; Bike running great, then I washed it. I tried to crank it up after washing it and notices smoke coming from under seat, bike not running but switch on. The little red wire from battery is very hot and the red wire from rectifier is very hot. Why?? When I unplug little red wire everything cools. With meter on battery and little red wire unplugged batt. reads normal but when I plug wire up the voltage drop significantly. Any ideas??

Post edited by: skydailey, at: 2007/10/11 11:24

sd, You might want to add the bike year/model and your location to your signature... Is this a Kawasaki? Guessing wiring codes from other models is a problem for me as I don't know them very well.

Sorry.. I fixed it in the subject. Atlanta Ga

Sorry.. I fixed it in the subject. Atlanta Ga

Sounds like the rectifier is bad. Did it get wet?

Yes it did get wet!! Is that a no no? Also, what happens to the path of elect. when the rect. goes bad? Is there a test to check it?

A rectifier in good condition can handle getting wet, but if the varnish is cracked and water gets in, it could be damaged.

Yes you can check it for a permanent short. If it's an intermittent short or a load-only short, it's difficult to detect.

A diode only allows current to flow in one direction. That is in the direction to charge the battery and power the bike. If the diode shorts, it allows current in both directions which means it will drain the battery.

If you have a manual, it should describe the diode check.

Post edited by: loudhvx, at: 2007/10/11 14:02

I guess I'll post the tests in case your manual doesn't cover it. This is just sort of a "work-in-progress" write up, so I may have to edit it for correctness or better details.

post your results for the resistance readings so we can have a look at them.

These tests are for rectifiers only (including those found on the 1977 KZ650 and some early KZ400's). They are not valid for rectifier/regulator combo units.

To test a rectifier, you can use an ohmmeter to check for shorts or opens, but these tests will be without any load. If the rectifier fails these tests, it's definitely bad, but if it passes these tests, then it may still fail under load and heat. Therefore, these tests can only confirm a failed unit, but cannot confirm a good unit.

When using an ohmmeter to check diodes, the exact readings can vary because different meters will affect the diodes differently. (Ohmmeters are not really ideal for measuring diodes.) However, we don't need exact readings, we only need a way to differentiate between forward and reverse directions on the diodes. When the meter is applied in the forward direction, the resistance reading will be lower than in the reverse direction. We'll call the forward reading "low-resistance" and the reverse reading "high-resistance". It will be necessary to measure several diodes in order to get a good idea of what "good" readings are for high-resistance and low-resistance on any given meter. Also, "good" readings can vary by roughly 10% to 20%, for identical diodes due to engineering tolerances etc.

To test the rectifier, we will have to pay close attention to which meter lead is connected to which wire. Also, the rectifier should be completely disconnected from the bike, and preferrably removed.

First, connect the red meter lead to the red rectifier wire. Then connect the black meter lead to each of the yellow wires individually. Each reading should be the "high-resistance" measurement. This verifies reverse-bias on the positive-side diodes.

Next, connect the black meter lead to the red rectifier wire. Then connect the red meter lead to each of the yellow wires individually. Each reading should be the "low-resistance" measurement. This verifies forward-bias on the positive-side diodes.

Next, connect the black meter lead to the black rectifier wire. Then connect the red meter lead to each of the yellow wires individually. Each reading should be the "high-resistance" measurement. This verifies reverse-bias on the negative-side diodes.

Next, connect the red meter lead to the black rectifier wire. Then connect the black meter lead to each of the yellow wires individually. Each reading should be the "low-resistance" measurement. This verifies forward-bias on the negative-side diodes.

Post edited by: loudhvx, at: 2007/10/11 15:05

Each test all readings were in the 800's no real difference in high resistance and low?? If you need exact I will do that.. Also battery was almost empty of acid all of a sudden!!

As long as you did no changes on the electrical from the last time it all worked, and you can't find any shorts in the wiring, it sounds like the rectifier is shot. and now the battery is probably a goner too.

Will it even start (leave the rectifier and regulator both unconnected)?

All readings are the same for all positions of the meter leads? That's bad, and unexpected, actually.

I would recommend this guy. He makes a rectifier for your bike specifically.
www.oregonmotorcycleparts.com/rectifiers3p.html