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Using a t500 switch with a gt500 wiring harness...

Posted: Tue Jun 15, 2010 9:32 pm
by moth_boy
Hi!
Let me start off by saying that I'm an idiot.
And my bike isn't sparking.

I have a t500 frame in which a reasonably well functioning PEI equipped gt500 motor and wiring loom were located, a conversion carried out by the previous owner.
I decided to switch the gt500 gagues to the t500 style where the ignition switch is located under the tank. To do so I needed to lengthen the wires between the switch and the harness which had been cut and butt-connected back together. I didn't notice that the wires coming off the switch were of different colors than the wires on the loom they were connected to.

I've found the gt500 wiring diagram on ozebook
Image
and the t500 diagram Image

But I can't quite make out what wires would be connected where if you were using a t500 switch in a gt500 loom?

Can anyone help? The colors on the loom are-
Red- Powered 12v
Orange- unpowered (what does this do?, out to lights?)
Black with yellow stripe- kill wire?
Black with white stripe- ground?

The wires on the switch are
red
orange
brown
grey

What should go where?

From my understanding of the gt500 wiring diagram,
the black/yellow wire kills the engine by grounding out the cdi?
Either at the kill switch or the key switch?
So if the black/yellow wire is disconnected at the kill switch and the key switch disconnexted, I should have spark when I kick the bike over with the plugs out or with one plug in. I have a crappy analog meter, but it seems I'm getting only a couple of volts to the coil.

Thanks for your help!
JD

Posted: Wed Jun 16, 2010 12:50 pm
by rbond
The black/yellow wire grounds the CDI. It gets it's power from the magneto, no battery, so if you disconnect the wire, kick it and it should start. The other two contacts on the GT switch provide 12v for the rest. Your next problem unless already done is the voltage regulator. Is it the GT or T unit? It would probably be easier to use a complete GT wiring harness than try to adapt the GT motor to the T wiring harness, not impossible, but slightly tricky. I have a GT myself, I had to make a new wiring harness from the magneto to the main harness with new block connectors. I had to make a 'translation' chart to make sure the new color wiring went to the right original wires on the main harness. The insulation on the wires was breaking and exposing copper and would not bend, so new wire! If you do not have a GT wiring harness at all, then this may actually simplify things by making a harness from scratch based on the diagram. You will need rectifier and voltage regulator for a GT to make the charging work properly, such that it is.

Posted: Thu Jun 17, 2010 7:52 am
by moth_boy
Thanks for your response!

In answer to your question, I believe I have MOST of a gt500 wiring harness. The bike was functioning reasonably well last year using that harness. With the black and yellow wire disconnected I still have insufficient juice going to the coil.
I'm wondering what the input voltage from the stator to the cdi should be. I replaced the internal ignition coils last year and the pulser. So I wouldn't think they'd be bad, but you never know!
JD

cdi

Posted: Thu Jun 17, 2010 8:48 am
by rbond
Go to the following web site and check the two ignition coils on the stator. I have had two sets of these go bad. They provide ALL the power for the ignition. http://home1.stofanet.dk/optik/suzuki/ignition-gb.htm
While you are doing this, go ahead and check all the coils, even the replacement sparkplug coil.

Re: cdi

Posted: Thu Jun 17, 2010 9:37 am
by oldjapanesebikes
rbond wrote:Go to the following web site and check the two ignition coils on the stator. I have had two sets of these go bad. They provide ALL the power for the ignition. http://home1.stofanet.dk/optik/suzuki/ignition-gb.htm
While you are doing this, go ahead and check all the coils, even the replacement sparkplug coil.
That's a great web site to know about ! 8)