• Ciao Guest - You’ve landed at the ultimate Guzzi site. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER - Use the CONTACT above if you need help. New to the forum? For all new members, we require ONE post in the Introductions section at the bottom, in order to post in most of the other sections. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have, have likely been already answered. DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back in and reply within 24 hours, or your post will be deleted. Note there's decades of heavily experienced Guzzi professionals on this site, all whom happily give endless amounts of their VALUABLE time for free; BE COURTEOUS AND RESPECTFUL!
  • Be sure to see the GTM STORE link also above for our 700+ product inventory, including OEM parts and many of our 100% Made-in-SoCal-USA GTM products and engine kits. In SoCal? Click the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work, and don't miss our GT MotoCycles® (not) art on the BUILDS tab above. WE'RE HERE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED - DO NOT EMAIL AND ASK QUESTIONS OR ASK TO CALL YOU.
  • There is ZERO tolerance on personal attacks and ANY HYPERLINKS to PRODUCT(S) or other competing website(s), including personal pages, social media or other Forums. This ALSO INCLUDES ECU DIAGnostic software, questions and mapping. We work very hard to offer commercially supported products and to keep info relevant here. First offense is a note, second is a warning, third time will get you banned from the site. We don't have the time to chase repeat (and ignorant) offenders. This is NOT a social media platform; It's an ad-free, privately funded website, in small help with user donations. Be sure to see the GTM STORE link above; ALL product purchases help support the site, or you can upgrade your Forum profile or DONATE via the link above.

Perplexing electrical issue - advice welcomed!

Julian Sudano

Julian Sudano

Tuned and Synch'ed
GT Contributor
Joined
Jul 25, 2021
Messages
62
Location
Los Angeles, CA
Hi All

My 1984 V65 SP has a really irritating electrical issue. The Italian electrical gremlins have finally struck!

When I turn the ignition on, and when the bike is running, I get no dashboard warning lights: no Oil Pressure light, Generator light, Neutral light, Hi Beam light, etc. As I rev the engine, the generator light comes on and stays on until the engine returns to idle. I also get no headlight, even with the light switch on. My brake light doesn't work when using only the hand lever.

This is the odd part though. When I brake, using both the foot pedal and hand lever simultaneously, ALL the dash warning lights illuminate!

I followed some previous advice on this forum and pulled apart the 15 pin Molex connector under the tank, and was able to restore the dash light operability, by playing with #4 pin which connects the front and rear brake circuit pressure sensors and dash lights. However, I pulled the front of the bike apart to grease the yoke bearings, and the issue came back. I was able to restore the dash lights again, by repeating this, but only briefly. It's now a permanent condition.

I'm at my wits end here, as I hate messing around with automotive electrical systems as I don't really understand them well. I have spent hours with my multimeter checking continuity on all of the circuits that seem to be interconnected, but haven't been able to find any faults. I've pulled apart the LHS switch gear - Light Switch, Flash/Horn Switch - but can't seem to identify any issues. One anomaly is that the head light will illuminate when the Flash Switch is pushed.

If anyone has any suggestions, hints or advice I would be grateful!
 
I'm not familiar with this bike but Is it possible to disconnect the generator and its associated regulator/rectifier and just have it on the battery, the reason I say this is when you rev the bike you have issues with the gen light. Either of those 3 could be compromised and putting an earth/12volts where is shouldn't be. Also check you have good earths with zero ohms where applicable. Bad earths in lamp fittings can cause all sorts of weird problems. Try to use an analogue meter and not a digital multimeter as the later has such a high input impedance it can give erroneous readings. You can even use a small light bulb with a couple of wires attached to check voltages and earths.
 
You must log in or register to reply here.
Back
Top