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Relay for the ignition
Posted: Sun Jan 26, 2014 7:21 am
by Allan k
I just added a small automotive 30amp relay, to give the ignition coils direct current from the battery. The voltage increase to the coils was about 0,5volt. Maybe not much, but combined with the new plug leads, and new wiring from the points and the coils, i hope it will give a small increase in performance.
The relay fits right behind the coils.
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 9:21 am
by oldjapanesebikes
A few folks I know have done the same mod - if nothing else, it unloads the current draw through the front wiring harness which can't be a bad thing.

Re: Relay for the ignition
Posted: Sun Jan 26, 2014 9:44 am
by CBWELLS
Just an FYI: Whenever you attach anything directly to the battery, it's a good idea to put a fuse in line as the first component. Without a fuse, the circuit is subject to catastrophic failure (read FIRE) if the wire should become shorted to chassis.
Of course you'll probably say, "Yeah, but what about the wire to the fuse? That one isn't protected!" Certainly true, but that's why ya keep the lead length to the fuse as short as possible.... to reduce its exposure. Lastly, if ya DO add a fuse & associated wire(s), you'll probably introduce more than a 0.5v loss in your new circuit with those parts. So your gain will be pretty much wiped out. You make your own judgement as to the relative odds of risk/benefit value.
Like they say, "Just sayin'!"
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 10:02 am
by Allan DK
A fuse will be added, for safety reason. Once added I will meassure the voltage loss.
Thanks for input.
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 11:06 am
by tz375
I added an in line fuse and relay to the ignition circuit of a GT750 and not only does it reduce the voltage drop but it also reduces the load and heat in the kill switch and main switch and it reduces overcharging. It's a win-win with no downside.
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 12:05 pm
by Suzsmokeyallan
While you're at it remove and clean all the contacts within the ignitions system and use dielectric grease in the cavities. Check the coil connectors six pin unit as well as the nine pin unit and the main harness three wire junction as well as the ignition switch connector,, you see where this is going. Clean and grease them all for proper continuity, you may suddenly add 0.5 volts in the process.
Have you flushed the ignition switch base contacts through the hole under the boot?? doing that and putting in some of the same dielectric grease is cheap insurance.
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 12:23 pm
by Alan H
Some soft rubber between the relay and frame will stop any chance of it 'chattering' if you ride over (say) a railway crossing or similar which might cause misfiring.
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 2:24 pm
by Allan k
New ignition switch, coil connecter six pin removed, and changed with new wiring all the way from points to coils.. .
A piece of 3mm neopren rubber, is there between the relay and frame, to protect both.
It is slightly visible on the photo
Here is a photo of the coils being rebuild.
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 2:25 pm
by Allan k
Another with new leads glued in place
Re: Relay for the ignition
Posted: Sun Jan 26, 2014 4:24 pm
by pearljam724
Is that just ordinary clear epoxy that you have used ? If so, I may try using some with the Rex Caunt coils to keep my spade terminals in place. I assume using clear epoxy wouldn't interfere with conductivity ? I may use that, if soldering them to the brass doesn't work.
Re: Relay for the ignition
Posted: Mon Jan 27, 2014 5:08 am
by Allan DK
Well i was hoping for the hard epoxy like glue but its a bit soft like rubber, but it seems to be strong enough though. Conductivity should not be an issue since the glue was put on after soldering and pressing in the plug leads.
Re: Relay for the ignition
Posted: Mon Jan 27, 2014 12:36 pm
by Alan H
Soft should be better as it will have less chance of cracking over time.