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General Category => General Discussion => Topic started by: ukdavo on March 06, 2016, 11:38:19 AM

Title: ignition/starter circuit, '79 1000SP
Post by: ukdavo on March 06, 2016, 11:38:19 AM
Hi. I'm tracking down an electrical fault in the starter circuit. I connected the red, white & green wires coming out of the ign switch (per Dave Richardson's post) When I hit the startere button I see a pretty fat arc thru the translucent case of the starter relay. & when I disconnect the ign wires from one another I notice that they are pretty warm. So I think I'm seeing a significant voltage drop thru the starter circuit. Could this all be faulty relay? Thanks, David
Title: Re: ignition/starter circuit, '79 1000SP
Post by: Tom on March 06, 2016, 06:46:36 PM
Check the thread on the T-3.  No sense duplicating efforts.
Title: Re: ignition/starter circuit, '79 1000SP
Post by: Chuck in Indiana on March 06, 2016, 06:51:42 PM
Does your starter turn if you jumper it? Sounds like maybe not?
Title: Re: ignition/starter circuit, '79 1000SP
Post by: ukdavo on March 06, 2016, 09:30:49 PM
I have been thru the archives. Not sure what the "T3 thread"  is.
The starter cranks fine when I jump it directly. Often, it won't crank when the key is in position 1. Turn the key to position 2 & it'll start cranking, & will then start if I switch the key back to position 1. I've pulled the switch, taken it apart, and contacts do look worn (not just dirty) so I have a new one ordered. I've got a new relay ordered as well, & I intend to wire term 30 direct to B+ using 12 g AWG and a fuse (probably 20 A). I just want to fault check as much as I can while I have it apart, hence the question about the warm wires. Again, can a faulty relay cause a significant voltage drop and warm wires?
Thanks from the always-useful responses, David
Title: Re: ignition/starter circuit, '79 1000SP
Post by: Stevex on March 07, 2016, 12:01:25 PM
Check the thread on the T-3.  No sense duplicating efforts helping with a link.
Sorted for you.

Davo, have a look here at the 'T-3' thread, it may answer your questions.
http://wildguzzi.com/forum/index.php?topic=82091.0
If not, keep the questions coming, there a some wiggly amp gurus on this forum who can offer some good advice.

Title: Re: ignition/starter circuit, '79 1000SP
Post by: Chuck in Indiana on March 07, 2016, 12:28:55 PM
Sounds like a dodgy ignition switch to me, but I'm no electrical guru. Here's the schematic..
http://www.thisoldtractor.com/guzzi007/schematics/1978_V1000_SP.gif
50 powers the ignition through the kill switch. Have you checked to see if you have power to the kill switch?
Title: Re: ignition/starter circuit, '79 1000SP
Post by: ukdavo on March 08, 2016, 08:03:38 PM
Thanks for directing me to the T3 thread. I will bookmark & save it. I've pretty much narrowed it down to "two problems at once:" worn ignition switch & bad (arcing) relay. I rebuilt the ign switch today - cleaned contacts, fresh dieelectric grease. Hopefully it will work. I've been waiting on a stock relay, but maybe I'll try a generic from NAPA. I'll wire the #30 term direct to batt. I still haven't gotten an answer to my "warm wires" question: Again, can a faulty relay cause a significant voltage drop and warm wires? I guess I'll find out when I hook in the switch & new relay & test the system.  Thanks again for the help, David
Title: Re: ignition/starter circuit, '79 1000SP
Post by: Chuck in Indiana on March 09, 2016, 05:24:08 AM
Probably should check the dielectric grease thread.. :cool:
http://wildguzzi.com/forum/index.php?topic=82086.0
Title: Re: ignition/starter circuit, '79 1000SP
Post by: Tom on March 09, 2016, 05:51:40 PM
It's possible that you may have a light coating of plastic over the internal contacts.  This could be build up that is contributing to the higher resistance.  Best thing is to scrape the contacts clean or wire brush them to remove all crud.