1982 GPz750 Regulator/Rectifier Advice Needed

According to my mechanic, the regulator is bad on my GPz750 which is killing the battery by over-charging it. Since most of the equipment on the bike is factory, I assume the R/R is as well. Should I just get a used ebay KZ750 unit? Are there better engineered, newer R/R's from more modern bikes that I should look at?

Stators, Regulators & Rectifiers
www.rmstator.com
www.electrosport.com
www.denniskirk.com/jsp/product_catalog/P...atId=&mmyId=1656
www.customrewind.com
www.regulatorrectifier.com
www.oregonmotorcycleparts.com
www.accel-motorcycle.com/
www.tpe-usa.com/ (Tim Parrott Enterprises)

Should I avoid the ebay units? The $30 ones with a 30 day return policy sound like a good deal when compared to the $100 new units.

Try Oregon Motorcycle Parts first as I've never trusted used electrical parts. They supposedly have a lifetime warranty on their parts.

If you go into "File Base" here on KZR, www.kzrider.com/filebase/cat_view/102-19...6-kawasaki-kz-750-r1
Then look at your wiring diagram. You will see that your R/R combo has a brown wire coming from Ignition switched power. This brown wire is used by the R/R to Sense the voltage of the battery. if the Brown Wire is Below battery voltage do to dirty contacts, connections etc. The R/R will see the Lower Voltage and make up the difference, then over charge your battery. you need to test for Voltage drop along this circuit. Start by measuring battery voltage and work forward, through your fuse panel, then on to the ignition switch, handle bar switch, etc. To test the problem, measure your voltage across the battery with engine running and 4K RPM. Then disconnect the Brown wire from the R/R, and with a Jumper wire connect the R/R end of the Brown wire back to the Battery Positive, and retest the voltage across the battery as before. See if the voltage is around 14.5v or so. You don't want it above 15v.
I think you'll find that the R/R is ok, and the Brown wire sense is the problem.

I appreciate the wiring info. A little research on the R/R that the KZ750R1 uses (SH530-12) revealed that it is fairly heavy duty, and is reliable enough to be used in both the Ninja 500 and Ninja 250 25 years later. Maybe the problem is the R/R, but I'm checking the cheaper option first.

Like Motor Head ssaid check the wiring. When I thought I had an issue with the regulator it was the brown wire just sitting in the connector and came apart when I tugged it.
Dont waste money on Ebay electrics.

There's another very usefull document in the filebase. Click on Filebase up top left and search for the Electrosport Fault Finding Flow Chart in "Non model specific" section. Very very usefull for troubleshooting charing issues
Good luck

I multi-metered away today and these were my findings:

1. The brown wire, at the connector closest to the R/R is down 1 volt from the battery.
2. The 1 volt is being lossed somewhere between the battery and switched power. The fuses that deal with the switched power are down 1 volt.
3. The R/R is likely the problem as running a wire from the brown wire directly to the battery results in no change in R/R power output (as high as 17-19 at 4k RPM),

Looks like I'll buy a R/R on Ebay since I plan to sell this thing once all the bugs are worked out. Has anyone tried an EX500 or 250 regulator in on a KZ? They all use the Shindengen SH530-12 R/R, and many of the Ninja ones can be had, with a 1 month guarantee, for $30.

Make sure your Black/yellow wire from the R/R is grounded, also the body of the R/R where it bolts down.
When you put the brown wire back to the battery, it was the R/R end, not the 12v switched end from the harness right? It almost sounds like the R/R is not seeing the voltage, or maybe it is defective.
You would want to get rid of that voltage drop as well.