battery still dying

[Anonymous]

hello. a few weeks ago my bike would not start all of a sudden. got a new battery, charged it, and put it in last night, rode it for a few hours. this morning the battery is dead again. i checked the no-load alternator output last night (yellow, green/white and blue/white cables) and it was putting out around 60 volts at 4,000 rpm. i didn't think it was bad for a twenty-something year old bike. i will have to check the rectifiers next. QUESTION: does anyone have a fool-proof test procedure of the whole charging system (esp. the rectifiers)? Clymer seems to be beating around the bush. They don't even tell you which fuses to take out to test the voltage going to the battery.

I'd appreciate any help, since this is robbing me of some good riding time.

my bike: '82 GS850G, 50,000 miles

[Anonymous]

same problem

just noticed that "user: my98xplorer" has a very similar problem to mine. this seems to be a beginning of an epidemic. too bad, couse the GS is such a sweet bike. i will check out the stator papers. but still would appreciate any help with diagnosing the source of problem. thanks!

[Anonymous]

stator papers

eh... where are they, the stator papers? i looked all around the forum. thanks again.

[IanFrancisco]

There are tests for the RR in the Stator Papers (Garage section of this site) but they are not quite accurate. The connections it describes are good to use, but the expected results are not. On a brand new Electrex RR I saw the .5V it specifies but not the 1.5V with polarity reversed. And this test was written by an Electrex guy! The factory service manual for the GS450 simply requires the RR to pass a series of continuity tests and does not specify any voltages. You will need a continuity tester, the simple light or buzzer type will work but I used the diode tester on a multimeter.

A rectifier is a diode bridge consisiting of four diodes. Diodes are designed to pass current in only one direction. The rectifier converts the AC voltage from the alternator (stator/rotor) to DC voltage. Sorry if this basic info is redundant. These tests are performed with the RR disconnected frrm the bike. So, connect the red (+) lead from your tester to the ground wire of the RR. There should be continuty from there to each of the three wires that connect to the stator. Reverse the polarity, ie, connect the neg. lead of the tester to the RR ground. There should be no continuity to any of the three wires going to the stator. This far, you should have done six tests. Now repeat, but connect the red test lead to the red output wire of the RR. There should be no continuity to any of the three wires going to the stator. Reverse polarity and retest. There should be continuity to all three wires going to the stator. Finally using the ohm meter portion, connect the test leads to the red output and black ground wires of the RR. There should be infinite resistance (OL or open line) or no continuity between these wires.

The other test in the Stator papers are good to use, especially the ones that check the ground wires and red output circuit. It's a good idea to go ahead and run an extra ground wire from the RR directly to the battery neg. and go thru the entire harness cleaning all connectors. Even a little corrosion can cause a faulty ground and overload the charging system. Make sure your harness is pristine before spending any money on expensive parts like the RR or stator.

It sounds like the stator is OK, although mine put out 55VAC @ 4500rpm when cold, and I saw 14VDC at the battery with everything connected and the motor running at 2500rpm. But, as soon as the motor was warm, charging voltage dropped from 14VDC to 12VDC, not enough to run the lights and keep the battery charged. I ended up replacing both the stator and RR with new Electrex parts ($120 + $140 - ouch!) but have had no problems since. Some folks have had bad luck with Electrex, there may be quality control issues there or they may have had wiring issues that caused new parts to fail. I'm keeping my fingers crossed!

Search for other posts. There's tons of conversations about charging system, RR, and stator problems on this forum.

[SqDancerLynn1]

MY opinion is that after a complete stator test & wiring check If they are good Replace the reg/rect

[IanFrancisco]

Re: same problem

just noticed that "user: my98xplorer" has a very similar problem to mine. this seems to be a beginning of an epidemic.

Well, it's not exactly the beginning of an epidemic. These GS's are famous (infamous? notorious?) for charging/ electrical problems. Maybe it's just the first time you've come across it. My GS450 is my first 'zuki, and it didn't take long before I found out about charging system woes the hard way. Welcome to the club! At least once they get fixed right they're good to go for a while. Hopefully a long while.

[Poot]

I think in this situation, it may be the R/R, since that is what is returning charge to the battery. I am just wrapping up the same problem on my 850. Took it to the shop, since I dont know jack about electrics, and was having a hard time working on my bike, coming home after continuos 12-14 hour days.



First things first though, clean all of the connections, including the positive leads (red wire) and grounds, and use some di-electric grease. It would be good to save a few bucks if this solved your problem. you never know!!!



POOT