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 Post subject: Electrics help please?
PostPosted: Tue Dec 29, 2015 2:48 am 
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Joined: Sat Dec 19, 2015 6:06 pm
Posts: 12
Location: New Zealand
model: 750 Sport
year: 1989
Hi,

My 89 750s has an odd issue. When it's cold the electrics will cut out entirely. No power at all. The starter does not work and the lights in the dash go out. Leave it a few seconds and it comes to life again and the starter fires her up fine.

I had the seat off looking at the wiring and noticed that the relay under the seat clicks off. Now, I'm not sure there is supposed to be a relay. Has someone before me dine the wiring mod? I've posted a picture here. The relay is a 12v fused thing and attached to a combined block with the flasher.

Is the setup I have here standard?


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 Post subject: Re: Electrics help please?
PostPosted: Tue Dec 29, 2015 8:01 pm 
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paso grand pooh-bah
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Joined: Wed Dec 05, 2007 12:35 am
Posts: 1571
Location: Newzealand
model: 906 Paso
year: 1990
That relay is where Id start looking . Check all 4 wires go where they should. One should come from the ignition sw to trigger the relay , and the other end of that should be earthed . There is a power in wire which should come from either the battery or the fuse box , and go to the main elect feed circuit . Seeing as how it all works eventually Id say all the wires arewhere they should be .... you just have a bad connection somewhere..... shouldn't be hard to find :)

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 Post subject: Re: Electrics help please?
PostPosted: Tue Dec 29, 2015 8:32 pm 
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Joined: Sat Dec 19, 2015 6:06 pm
Posts: 12
Location: New Zealand
model: 750 Sport
year: 1989
Thanks mate. I'm inclined to agree with you. The relay could be failing too. Am I right in assuming that the relay on the left with the plastic lid is non standard? I guess it doesn't matter if it is or not, it just needs to work :). But I'd be keen to know either way.


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 Post subject: Re: Electrics help please?
PostPosted: Tue Dec 29, 2015 10:54 pm 
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paso grand pooh-bah
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Joined: Sat Sep 03, 2005 12:00 am
Posts: 1309
Location: SF Bay Area
model: 750 Sport
year: 1990
That does look like what is under my seat. Looks all stock to me. Yes, one has a fuse in it.
Mine has a zip tie around the two relays and the block to hold everything in place. I guess a previous owner had some issues, so just left it there.

If you haven't yet, pull every connection apart, clean it off, put some silicone dielectric grease on it, cycle it a few times, and put it all back together. Just making a breaking the connection a few times will vastly improve the connection originally made 25 years ago, and the grease will keep it from corroding further.

Another modification is to drill and tap one of those fins to ground the ECU housing, as well as the voltage regulator up front. Ground loops make for funny gremlins.

Cheers, Phil

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Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.


Last edited by ducinthebay on Thu Dec 31, 2015 2:17 am, edited 1 time in total.

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 Post subject: Re: Electrics help please?
PostPosted: Tue Dec 29, 2015 11:22 pm 
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Joined: Tue Mar 13, 2012 9:02 am
Posts: 315
Location: The Blue Mountains, NSW, Australia
model: other
year: 1988
And the same as when I had mine, all looks as it should


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 Post subject: Re: Electrics help please?
PostPosted: Thu Dec 31, 2015 10:31 am 
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paso grand pooh-bah
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Joined: Sun Jul 18, 2004 12:00 am
Posts: 5090
Location: southern Germany
model: 750 Paso
year: 1987
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pull every connection apart, clean it off, put some silicone dielectric grease on it, cycle it a few times, and put it all back together.

Clean the contacts put them together and then apply dielectric grease. It`s an insulator you don`t want that on you elecrical contacts.

I wonder why the protecting rubber boot on the connector to the Digiplex is missing.


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 Post subject: Re: Electrics help please?
PostPosted: Thu Dec 31, 2015 5:26 pm 
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paso grand pooh-bah
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Joined: Sat Sep 03, 2005 12:00 am
Posts: 1309
Location: SF Bay Area
model: 750 Sport
year: 1990
Yeah, the name dielectric grease kinda infers an insulator, but mostly it is a barrier to water, dirt, normal grease and oils, and anything else that may conduct electricity from the connection, or promote corrosion. It seals your connection from intrusion of water and debris that will degrade and oxidize the connector bits. Silicone grease is often sold as Tune Up Grease at the autoparts store, and has been in use for years. Its wonderful on your sparkplug caps, as it makes it easy to remove them, and seals out any dirt, dust or moisture.

Any connection should be metal to metal in the first place, and some grease is not going to improve that. But if your connectors are basically good, the grease will help seal that connection on a very micro scale, and keep the metal from oxidizing further.

Cycling the connection will make a great connection today, but oxidation will degrade it slowly over time. Gold is the ideal connector, but short of that, a touch of silicone grease helps brass and zinc live a longer and happier life.

Cheers, Phil

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Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.


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 Post subject: Re: Electrics help please?
PostPosted: Sat Jan 02, 2016 4:48 am 
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Joined: Thu May 16, 2013 10:07 am
Posts: 18
Location: Australia
model: 750 Sport
year: 1988
Mine did the same thing, although yours looks different to mine under the seat, mine has 2 X CDI's, I found an 8 pin connector in a black rubber boot under the handlebars on the right hand side that was a bad connection, used some contact cleaner to clean the pins and voila she was all good again, i found that when i turned the steering and the wiring loom moved, the ignition lights would go on and off, if no contact cleaner use a jewellers screwdriver and scrape the pins clean...... must disconnect the battery first though !...... its really hard to put the smoke back in.... once it comes out of something important like a CDI or a regulator


Last edited by mickyfinn on Sat Jan 02, 2016 5:01 am, edited 1 time in total.

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