Charging Problems, please help. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 6 (permalink) Old 04-15-2006, 04:55 PM Thread Starter
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Charging Problems, please help.

New Yuasa AGM battery has already been installed. (Schweet!)

Using my Kawasaki Service Manual and the ElectroSport Industries troubleshooting fault finding flowchart for motorcycle charging systems, I determined the RR was defective. The connector on the RR was melted/corroded. I ordered a replacement and installed it last night. After installing the new RR, voltage equals 12.5 volts at idle, 12.8 at 2500 rpm, and maybe 13.0 volts at 5000 rpm; but it takes a while to get there. Again I used the ElectroSport Industries troubleshooting fault finding flowchart for motorcycle charging systems and it pointed me to a bad connection in the positive lead the RR to the battery (+). I verified every connection in that circuit with my digital meter and there was a minimum of .2 ohms (just about ground). I also verified the (-) side of the wiring. Same results. I disconnected, cleaned, applied dielectric grease to all connectors and I am still having the same results. I checked the stator and rotor according to the troubleshooting chart and they indicate good. One other thing. The connector at the RR gets very hot and will eventually start smoking. Yikes.

Help is truly appreciated.

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post #2 of 6 (permalink) Old 04-16-2006, 02:27 AM
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You clean the RR connector ?
seems to be Yes !
It seems that you have harness corroded around pins of connector
may be you have to disassemble the connector and check all the pins and cables.
You can plug each pin manually without the plastic pin cover
just take care of take notes to be able to remount it later

just my two cent
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post #3 of 6 (permalink) Old 04-16-2006, 03:39 PM
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The R/R could be defective internally.There's a series of resistance measurements you can make between the pins of the R/R to help determine if it's bad. The values are listed in Clymer's. That connector does get hot. Several people have cut it out and replaced it with indivdidual spade plugs on the wires. I'd make sure the R/R was ok first though.

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post #4 of 6 (permalink) Old 04-21-2006, 12:07 PM Thread Starter
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Thanks for the advice. I have verified all connections and bypassed the harness connector. Here is the latest.

With the Headlight and Taillight fuses removed, the charging system works correctly. Engine at 2500 RPM, battery-voltage equals 13.5. Engine at 5000 RPM, battery voltage equals 14.6.
Whenever one of the fuses is put back in, the charging system does not work. Battery-voltage is now 12.3 - 12.8 depending on RPM.
Last night during extensive troubleshooting, I was able to the battery to start charging for a short period of time with the fuses installed. Now I am hearing chattering from the Junction Box when the two fuses are removed and the charging system is working. Once again though, as soon as one or both fuses is installed, the chattering stops and the charging system stops working.
I am thinking maybe a relay inside the Junction Box is not latching or unlatching and this is the problem.
Any thoughts??
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post #5 of 6 (permalink) Old 04-21-2006, 07:48 PM
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I had a similar problem on a '93 VN750 and the actual RR was fried.
Try this:

- Test the resistance between the RR conector and the junction box connector, if the wiring is old is posible you are lossing too much voltage in the wires, the original cables from the RR to the junction box seem a bit on the small side for the rated power output of the RR.
- With the motorcycle running see what voltage you see between the following points.
- Battery positive and the negative of the RR conector with and without load (lights) if you should be able to see a diference of about 1 volt or less, if you see more the cables are old.
- Battery negative and the negative of the RR conector if you see more that 0.5 volts your cable is old.
If you see any of this problems here's my advise:
With some cable (14 or 16 gauge works)use those crimp-on cable connectors (so you don't cut any of the original cables) run an extra ground cable from the battery post to the RR conector (as close as you can) and run one cable from the positive of the RR conector to the juntion box conector. This will cut you voltage losses due to resistance in the original wiring and reduce the load to the RR wich makes it very hot.
Mines's fix this way and the RR does not get as hot as before... if you see that this does not help you RR is likely the one to blame.
All this material can be had at your local RadioShack...

Hope this helps
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post #6 of 6 (permalink) Old 05-12-2006, 09:07 AM Thread Starter
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Many thanks for all of the suggestions.

After many hours of scratching my head and extensive troubleshooting; all indications point to the “evil” stator” as the defective part.

To summarize; the system will charge without a problem until a major load is turned on; i.e. Headlight and/or radiator fan. Resistance readings indicate the stator is shorted to the engine case.

I am currently getting myself in the right frame of mind to tackle this job once the parts arrive.
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