Charging System Quick Test Advice

[DaveP]

I just ran the quick test and would like to get advise on where to look next as the results weren't quite in the proper ranges and maybe even going in the wrong direction. 1981 GS650L.

Battery was just taken of the battery tender where it was all winter and installed in the bike. Multi-meter was connected to the battery cables with clips.

1. Key-off: 12.9 volts.
2. Key-on 10 seconds w/lights: 12.3 volts.
3. Idle: 13.3+, volts were continuing to climb while idling.
4. 2,500 RPM: dropped to 12.9 volts. Returned to 13.4 volts when back at idle.
5. 5,000 RPM: dropped to 13.2 volts. Returned to 13.5 volts when back at idle.
6. Key-off: 13.2 volts.

Something is not right, so moving on to Steps #2 and 3, I am not clear on where you would connect to the leads of the R/R. Are there intermediate connection points somewhere along each lead that you could make connection to?

Thanks,
Dave

[Nessism]

Dave,

First step to fixing the GS charging system is fixing the wiring.

The stator wires should feed directly into the R/R, bypassing the factory harness.

Make sure the R/R has a proper ground, adding a jumper direct to the battery itself if necessary.

Once you accomplish these things, then do the Quick tests. Not before.

[posplayr]

Your measuremdnts are probably indicating bad connections and poor grounds. Ed is correct; if you follow gs charging health it outlines the basic steps to improve grounds and potential points of high resistance in the fuse box. After cleaning redo the quick test. If the numbers rise you are on the right track. You can move to revised phase A to see if the resistance is on ground side or plus side.

[DaveP]

Thanks. A little more guidance needed. From the wiring diagram, I have three wires coming from the stator. Yellow, Blue/White, and Green/White which I believe are exiting the engine through the starter cover as a bundle. Each of these wires needs to be traced back to the rectifier and replaced? Wire size? Any distance from either component to make the new connections or just enough to eliminate much of the old wiring and harness?

Thanks,
Dave

[bonanzadave]

Hack off the old connector joining the 3 stator wires to the RR. Strip back the insulation and then join the wires with a GSR approved splice or butt connector using the proper crimper. That old connector makes less than bad electrical connections so its best to just get rid of it. Now find the RR ground wire and make a good electrical connection right to the neg batt terminal.

[DaveP]

Thanks. I will give this a try soon.

[Dragon Breath]

Generally, there is no need to replace any wires or even any connectors (unless they are physically bad).

Follow the three wires from the stator. You will see that two of them are connected to the R/R, the third one disappears into the harness.
Follow the three wires from the R/R. You will see that two of them are connected to the stator, the third one disappears into the harness.
Separate the two connectors that disappear into the harness, connect the third wire from the stator directly to the third wire on the R/R.

Ensure you have a good ground on the R/R, test your output voltages again.

[BlueSN]

Hi,
Katana 400 138v AC even between all phases... double what it should be ? I would have thought. Looks to be all stock as from factory, never had flywheel off. Have only ever seen this higher reading once before on an SR400. Anyone know what is up with this stator. Cheers

[posplayr]

Hi,
Katana 400 138v AC even between all phases... double what it should be ? I would have thought. Looks to be all stock as from factory, never had flywheel off. Have only ever seen this higher reading once before on an SR400. Anyone know what is up with this stator. Cheers

you should start tart your own thread. Are you measuring at. 10k rpm ? The factory spec is typically 5k rpm. Also check your meter using your local house wiring to make sure it is reading correct. 230 vac in. NZ?

[BlueSN]

just learning my way around. test at 5-6000rpm. meter check at mains = 236v. Is it possible that phases are bleeding together giving double the ac voltage ? Has fried Reg/rect and reluctant to plug another in at this voltage.

[posplayr]

just learning my way around. test at 5-6000rpm. meter check at mains = 236v. Is it possible that phases are bleeding together giving double the ac voltage ? Has fried Reg/rect and reluctant to plug another in at this voltage.

Not really any way to double the output. 3 phase is 120 degrees apart and going to 180 degrees would still not produce two to three times the leg to leg rms voltage short of spinning the engine at 15k rpm

[DaveP]

Back to our regularly scheduled program. Had a few minutes today to start tracing the wires. Before I start cutting things apart, was hoping for confirmation that I am in the correct spot. This connector comes from the R/R and is located above the battery box. I disconnected and moved above the frame for the picture.
IMG_4922.jpg

Seems to be in agreement with the wiring diagram, but not quite the same as the procedure described above? This connector has four wires: white/red, red, yellow, and white/blue.

Thanks,
Dave

[DaveP]

Condition of the existing connector:
IMG_4923.jpg