76 GT500 Not Charging

[jabcb]

You are correct.

I updated your pic to make it a littler more clear:

gt500wire_tympanium.jpg

[MonkeyWrenchCycles]

Thanks!! Im gonna wire it up right now.

[MonkeyWrenchCycles]

It Lives!! Charges good again. Thanks for all the help everyone. It is much appreciated.

[CJF]

I've been following this thread because I'm also having some problems with my GT500 charging system. My rectifier and regulator have been swapped out for the Boyer Powerbox which has a reglator/rectifier and capacitor in one. It looks almost identical to tympanium in terms of wiring. It has two yellow wires going in and a red and black.

I have the yellow/green and red/green wires hooked to the two yellows, but not the green/white. I currently have the green/white going directly from the charge coil to the left hand switch (which is what I thought the wire diagram showed?)

My symptoms are that the volts are fine 13-15v when the light switch is off, but when the switch is on, it drops down to 7-9 volts and drains my battery (to the point that the battery was damaged). If I try combining the green/white and red/green to the yellow from the powerbox, should this eliminate my issue?

Also, the green/white needs to continue on thru the loom to the left hand switch. Do I need to splice off from the green/white, red/green and yellow connection and run the green/white to the left hand switch? Or, do I connect the green/white going to the left hand switch to the red coming out of the powerbox? This part of the diagram is a little confusing.

Help would be a appreciated!!! I already ordered a regulator/rectifier from oregon electronics thinking the powerbox was the problem and I may not have needed it!!

[jabcb]

Took a look at GT500 rectifiers on eBay.
They have only 3 wires going to the latching connector: R, Y/G & R/G

The T500 alternator has 3 wires: Y/G, R/G G/W

So the GT500 should have:
stator Y/G connects to rectifier Y/G
stator R/G connects to rectifier R/G (for charging coil)
stator G/W goes to light switch, switches to R/G, light switch R/G connects to rectifier R/G somewhere in wiring harness (for lighting coil)

Its likely that the PowerBox is ok. Which one do you have?
Looks like your lighting coil is not working. Possible causes: dirty/loose connector, light switch problem, bad lighting coil, or problem in wiring.

To check the stator:
1) check resistance between G/W & Y/G wires, should be about 1 ohm
2) check resistance between R/G & Y/G wires, should be about 1 ohm

With stator & PowerBox disconnected, check wiring:
1) check resistance between Y/G at connector for stator & Y/G at connector for rectifier, should be about 0 ohms
2) check resistance between R/G at connector for stator & R/G at connector for rectifier, should be about 0 ohms
2) with light switch on, check resistance between G/W at connector for stator & R/G at connector for rectifier, should be about 0 ohms

(You won't get a reading of 0 ohms. You'll get a reading near the multimeter's internal resistance. Touch the meter leads together to get the internal resistance.)

Combining the stator R/G & G/W, and then connecting directly to the PowerBox will bypass part of the wiring. If this bypasses the problem, then it will solve the problem.

[CJF]

Thanks for the advice. I checked all the settings you mentioned and they checked out ok. I ended up trying hooking up the green/white wire from the charge coil to the yellow on the powerbox and then the green/white from the left handlebar switch to the red wire on the powerbox. Problem solved I know have 13+ vbolts when the light switch is on and off. Really appreciate the help!

[citizenbanana]

This is how I mounted the Tympanium regulator/rectifier.
Its larger than the T500 regulator. I don't know where the GT500 PEI box is located -- you might need to mount the regulator/rectifier in a different way. Also, one of the bolts attaching the battery box will need to be replaced with a shorter bolt.
T500_tympanium.jpg

I modified this T500 wiring diagram to show the changes: http://www.ozebook.com/compendium/t500_ ... 00wire.jpg
Here is the modified diagram:
t500wire_tympanium.jpg

The Tympanium ground wire is brown as I've shown.
I used a green wire because its commonly available.
I soldered the 3 "Y" wire connections ( yellow to green & green, red to red & red, black to black & black).

The 4mm bullet connectors are available at http://www.vintageconnections.com/" onclick="window.open(this.href);return false;

Hi Jabcb,

Went with the tympanium. Wired it up per your diagram. just trying to test it out (have the harness out of the bike) have power going to the tympanium, ground is good. But no power coming out of either yellow wire. Lost all my lights etc. Did I get a bad unit?

[jabcb]

The yellow wires receive the AC output from the alternator. The yellow wires have no voltage when the motor is not running.

[joethebike]

I installed the Tympanium on my T350 and it works very well.