Testing a Regulator/Rectifier on a KZ650 ???

Hey guys I need some help with my 79 KZ650D-SR, the bike doesn't charge the battery. I checked the AC voltage coming from the alt. It puts out over 75V AC. If I check the voltage at the white and red wire out of the regulator it shows battery voltage which is like 11.7V or so. The regulator also gets pretty hot even when the engine is only run for 5 mins. I got directions on testing the regulator from another post on this site, it said to disconn. connector at regulator, and check the ohms by placing the black meter lead to the black wire, and then the red lead to each of the yellow wires one at a time. You are supposed to do this with the meter on Rx1 and Rx100. However I never heard of a meter setting like this, my bluepoint meter only has regular ohms. and I get like 6-8 M ohms, which is actually 6-8 million ohms. I don't know if I am testing this correctly or not, and what the readings should be. I didn't know if any of you guys have a good one you could check for me to compare results, or if anyone knows what the ohms should be between these wires? Also does the regulator have to be grounded (bolted down) to work correctly, and to be tested? If anyone has any info please let me know, this is driving me crazy. And if anyone has one they want to sell me let me know.
Thanks alot, Derek

What you have is called an "Auto Ranging" meter, so there is no need (or even any way to do it) to switch ranges, it does it automatically.

Rx1 is ohms
Rx1000 is K ohms
Rx1,000,000 in M ohms

If the reg/rec is getting hot, then I'd say that it is dissapating current as heat, probably because you have a bad ground connection (could be a bad + connection as well, but I'm guessing ground).

I hope the pic shows. I know you tested the black and yellow wires from the regulator/rectifier, but maybe those same wire's connections circled here are dirty, and messing your system up. My electrics went batty one day, and this connector was almost melted. I still don't know what exactly caused my problems, but when I rewired this connector things have been great.



Post edited by: OKC_Kent, at: 2005/11/08 22:37

Thanks for the replies. when you say a bad ground do you mean the regulator itself being grounded to the mounting bracket? or a different ground.
thanks

How old is the battery?
Is the voltage (at the battery) above 12V when the bikes is off?

Post edited by: mariozappa, at: 2005/11/09 09:02

The reg/rec has a ground wire, it don't ground through the case.

Derek... I would approach this differently since I am not an electrical guru... Was the AC voltage you tested for within spec for your bike? If so, the stator or alternator is OK... NEXT step I would take is to buy a small hydrometer. These are big eyedroppers that have colored balls in them. Get the smallest possible from an autoparts store. It will come with a small piece of hose you put on the end and stick into each hole in the battery. You draw in some fluid and the balls in the hydrometer will either float or not float. The legend on the packaging will allow you to determine the health of each cell. You might have a bad cell on your battery and testing the reg/rec isn't necessary. If ANY cell is marginal, replace the battery. It is common for KZ batteries to have a bad cell. Next step, if the battery checks out good is to check out the reg/rec. First disconnect electrical connections and clean and reseat after dabbing with some dielectic grease. Then start the bike and measure battery power at idle. It should be nominally 12.5 VDC at idle. If it is less, then the reg/rec is mostly likely in need of replacement as you have already verified AC feeding it, battery health and connections. If you do get 12.5 VDC, rev engine to 4K rpm and retest voltage at battery. It should be just under 14 VDC. Anything significanlty less or MORE and the reg/rec is bad. I don't really understand the testing you are doing but the steps I just detailed will allow you to quickly track down your charging problems. Oh yeah, I am sure you have already cleaned and tightened your battery connections at both the pos and neg terminals and their connections on the solenoid and engine respectively. Also, there is a junction box with a various LARGE connectors near your battery. The blue one comes from the stator (or generator or whatever is on your bike)... pull these connectors; spray with contact cleaner and coat with some dielectic grease. Anyway, hope some of this stuff helps. I am pretty sure if you go through all the stuff I suggested you will find or fix your problem. Good luck.

The battery is new. The alternator puts out 75V AC or so. The battery has 12.3 to 12.6 volts with the bike off. After I start the motor the voltage does go down to like 11.8 or so, however this is after a couple starts, and the battery not getting charged which is obviously the problem. I also don't understand why the battery has anything to do with the problem. The alternator/stator puts out a voltage (75V or so) the regulator (if working correctly) then regulates the voltage and puts it out a DC voltage under 15 volts, so basically once the engine is started the battery voltage itself shouldn't be an issue, and shouldn't have any effect on the charging system itself, correct? The connectors and wiring all look good, besides I am not testing voltage at the battery, I am testing it right at the white/red wire coming out of the regulator, this one should put out a higher voltage than the battery has so it can charge the battery. Basically all I really need to know is what the ohm specs are of the regulator. As stated above the directions in the manual are for a non auto ranging meter, so you ignore the Rx1 and Rx1000 ohm readings, which then means the reading I get is going to be different than what the manual says. I listed above in my first question how I went about testing the regulator. Basically just wandering if someone out there could disconnect the connector on their regulator, use your meter on ohms, and place the black lead on the black wire prong, and the red lead on each yellow wire prong one at a time, again keeping the black lead on the black wire prong the whole time, and looking at what reading they get with the red lead on each yellow wire one at a time. Obviously you'll be testing the side of the connector that goes to the regulator. The reading should give you a normal number but will probably have a K or an M beside it. If anyone does this please indicate the numbers you get and if it is in K ohms or M ohms. This would be a great help. I think it's the regulator, however I bought one off ebay that supposedly was off a running bike, and I put it on, still no charge. I tested both regulators with the same meter and I get totally different readings. I just don't want to keep throwing parts at it, and spending all kinds of money. I just need to know what reading a good one has. Thanks alot for the replies so far

Your theory on the charging system is sound. I think you're on the right track in suspecting the reg/rect unit.

An ohm test is often not very telling on reg/rect tests. If the reg/rect is even slightly different internally than what the manual uses as a test unit, the ohm readings can be very different. You are measuring non-linear devices like diodes and SCR's which can vary a lot (unlike resistors).

To be accurate, a test would require you to measure identical units with identical meters. When measuring non-linear devices, the meter's internal voltage can affect the reading. Different meters may use different test voltages for measuring ohms.

If you're certain all the wiring checks out, then I would say it's proabably time to get a replacement reg/rec. You can find them cheap on ebay. You can use a reg/rec from other bikes too.

Here is a free, very good fault finding flowchart you can download. It's at;

www.electrosport.com/electrosport_fault_finding.html

under "tech support"

Post edited by: ~DW~, at: 2005/11/09 23:33

Actually, I had a similar problem. I had good AC coming out of the stator, but the bike wasn't charging despite me buying a new RR. For me, it was a lousy connection at the main fuse.

A really good test for the charging system is to disconnect the red/white from the bike and connect it to an outboard battery. You'll have to rig up some special connectors and wires to make it work (the black of the RR goes to the outboard battery neg. and the red/white to the positive - the yellows have to be bridged back to the stator). If it charges the outboard battery, your stator and RR are probably fine. In which case you can start looking at the wiring harness.

If the outboard battery doesn't charge, you'll know it's the RR, since your stator seems to be working good.

Good Luck!

Well, you asked for help and I offered some. I suggested you test your "new battery" as a dead or dying cell will make all the regulator testing in the world an exercise in futility. Even an new battery can have a dead cell and the battery should be check in any troubleshooting methodolgy before checking resistance on other components. I repeat, if the battery voltage is about 14 VDC at with the headlight on at 3500 rpm, your regulator / rectifier system is operating fine and the problem likely lies in the battery itself or connections. Good luck.