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Weird electrical issue

Julian Sudano

Julian Sudano

Tuned and Synch'ed
GT Contributor
Joined
Jul 25, 2021
Messages
61
Location
Los Angeles, CA
1984 V65 SP

I seem to have finally developed the legendary Italian electrical issues on my bike.

Problem started off as an intermittent one but is now permanent. When I turn on the ignition switch, prior to hitting the start button, I don't get any warning lights on the dash - Oil Pressure, Generator or Neutral. The beast starts alright, but still no idiot lights. I usually ride with the headlight on full time, and that warning light also doesn't come on, unless I put the Light Switch in the Off position!

The other day I noticed that as I pulled up to a traffic light and was braking using only the foot pedal, but then used the hand lever, all of the dashboard warning lights came on. Sure enough, by operating the hand lever with the foot pedal depressed, I could make the lights flash on and off. Also, when I was using higher revs, the Generator light would come on, but then go off at idle speed.

I have checked the starter relay and it has good resistance and the magnet works. Pulled the ignition barrel and couldn't find any issues there either. All fuses in the fuse box are good. I did recently have to replace the Voltage Rectifier as one of the diodes had died.

I'm beginning to suspect that the switch gear on the LHS on the handle bars may be broken as that seems to be where the warning lights get their electrical supply from if I am reading the wiring diagram correctly? Otherwise I'm stumped and I hate electrical issues!

Are those handle bar switch clusters serviceable, or is it a part that needs to be replaced when it malfunctions?

Any input appreciated!
 
First think to do with these older machines is to disconnect every harness connector, then clean with contact cleaner, then reconnect. Most electrical problems with these older bikes is corrosion at the connectors. Also since you are a contributor, you have access to the schematic in the downloads section.
 
So, you have to understand, most of those idiot lights are permanently fed by +ve, and for example, neutral or oil pressure bulb just needs ground to go "on". The ground comes straight from switch. In case of generator, one end is permanently fed by +ve as we said, other - by nothing; until generator starts to make juice, and then +ve appears there, making bulb off. So, I'd say your problem is with general supply of +ve to the idiot lights. The wiring diagram will definitely help, it isn't much complicated. Trace where +ve comes from, I believe it will come from one of those connector blocks, 12-pin or 15-pin, and problem is there - not in the panel, but under the tank.
 
OK - that makes sense. I did clean the connector blocks with electrical contact cleaner which worked...temporarily.

Appreciate the input - Cheers!
 
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