Got her started

[smokin]

I got the 72 GT750 started sounds real nice, been tweeking the carbs and getting the air out of the oil lines so far she sound good and no leaks, can't ride her yet prepping her for paint. I have one problem before I started her up all the electrical was working fine, now I have a problem with the brake light, tail light and parking light are not working the brake light works but comes on very slow and dim, head light, turn signals, gauges work, runs fine except for the tail light section, checked all the connections and there OK, I went threw the harness and fixed what looked to be bad before I put her together, any ideas what might be wrong?

smokin

[BRP Tourer]

sounds like a bad ground somewhere, maybe engine to frame

[TheMarkedMan]

I have a similar problem on the 74 Buffalo I picked up...my problem (though I haven't addressed it yet fully), seems to be the harness clip that's wrapped in a rubber sheath right under the passenger part of the seat...this kills my brake light, my running light, etc....
Seems to be an issue, should be an easy fix....
I'll let you know what I figure out....

[smokin]

I'll start looking around and see what I find. Thanks for the help.

smokin

[smokin]

Found the problem spent a whole day trying to find why the rear brake light system wasn't working, checked the ground, connections, voltage regulator and tested for shorts nothing, I was getting less than a volt through the braking system, I had a voltage meter hooked to the brake wires and reading .03 volts, so I started to bang on the voltage regulator the voltage started to climb, kept banging and its at 10.5 volts pluged in the tail light now it's working, I'll have to get a replacement in case this one goes out.

Smokin

[oldjapanesebikes]

I'm thinking that if everything else works forward of the regulator, and the engine runs, then your regulator is fine. You can confirm that if you put a meter across your battery and run the engine up to 3000 rpm - if you read a voltage increase up to about 14.5 volts then the regulator is working.

By banging on the harness connection panel where the regulator is mounted, all you are doing is disturbing the various wire harness connections and the harness itself. My bet would be bad grounds (easy to confirm with some scrap wire run from the battery negative to frame connections at the rear), the harness connections just behind the battery, a damaged harness where its clipped to the frame by the battery, possibly a bad connection in the headlamp, or the connection under the tank.

[smokin]

Hey Ian, I checked the ground in the tail light, checked the harness, connections, tested for shorts, I didn't have the head light bucket on so it wasn't grounded (getting painted) but the tail light was working before I started it, everything else worked after that, the only thing I found was low voltage going to the tail light couldn't figure out why it was getting low voltage in the brake system, had the voltage meter connected to the brake when I decided to tap on the regulator, voltage started to rise been working since the battery is charging, I don't know why that fixed the problem just one of those thing you can't explain I'll let you know if I have a problem later.