Understanding the Coil Mod?

Ok so I started my coil mod last night. I get a really crappy spark and my plugs foul out rather quickly so I'm doing this in hopes that it'll help.

I do plan on going with a DYNA S system and new coils later this summer, but for now this coil mod will have to suffice.

My question is, you have the red/yellow wire that comes from the harness right then slits into 2 wires going to each coil. So the relay #87 is what now splits and goes to the two coils, but is it the other single end of that yellow/red wire that originally powered the coils that goes back to the relay #86 for the trigger? Or is this some other yellow/red wire and the original one just doesn't get used. I suck at electrical and am trying to learn this stuff so be patient with my dumbass Qs.

Also, there is an additional note on the COIL MOD Instructions that talk about some power wire or positive wire that comes from the points/dyna that also ties into the Trigger, but I don't see that on the following diagram. Am I missing something?

I've got the ground ot fram from #85 - easy, I've got the power from the starter relay with inline fuse on #36, #87 to power the coils seems easy, I just want ot make sure I'm making the right trigger connection by putting that other end of the yellow/red wire back to #86?? And whether or not I need to worry about this mystery wires from the points??



Thanks

Post edited by: MattBlack, at: 2006/05/24 13:10

Look at the diagram .

The single red and yellow, just before the split to the coils, goes to the RELAY WINDING. The other side of this relay winding goes to ground. This is the control portion of the relay.

The two red and yellow that were connected to the single red and yellow go to one of the SWITCH terminals on the relay. Te other switch terinal goes to the battery via a fuse.

You have done nothing to the points side of the coils.

Before the mod:
All the power to the coils followed a round about path to the point where the red-yellow wire splits.
After the mod:
The round about path is still there but instead of supplying the coils directly it controls a switch which connects the coils to the power source by a much more direct path.

-Duck

Maybe, I should pop in... OEM wiring... power from coils goes from fuse area, through the ignition switch through the kill switch. There this power comes OUT of the kill switch on a yellow/red wire. This wire goes into a major connector that connects the right hand switchgear with the main harness. It comes out of the connector still yellow/red and along the harness yellow/red. It comes out of the harness over your carburetors in a dual female connector.

What this all means is when you turn the key on and have the kill switch in the RUN position, there is power ~ 12VDC at the dual female connector.

The factory plugs in two wires, BOTH yellow/red to the dual female connector and these are then run to your coils and connected to provide power.

When you do the relay mod, remove the wires going to the coils by undoing them at the coils and unplugging them.

The 12VDC that HAD been used to power the coils will now trigger the relay closed. Put a male barb type connector on a wire. Plug this connector into the dual female connector. Take the other end and connect it to your new relay trigger position #86.

IF YOU HAVE A DYNA S (and you don't), the Dyna S requires power (12VDC). To power it, it will be spliced into the same power as powered the coils. They give you a 3 way splice. You can either run a 3-way wire OUT of your relay and use power from the relay or use the unused half of the dual female connector where you would plug in another wire next to your trigger wire and run this wire to the Dyna S power wire (red wire I think). Since you have a points ignition, don't worry about it at this point.

Yes, the red/yellow that went to the coils goes to 86 and 87 goes to the two coils now.

Here's a wiring dia. when using a Dyna:

.

Thanks guys, got it all doen and the bike starts and runs fine. The relay clicks on and off when I turn the key.-- I'm assuming that if I didn't do it right the bike wouldn't start?

Didn't really notice any fatter spark, but I still have to check the coils to make sure they aren't on the way out anyhow.

Thanks for the help guys. This should tide me over until I upgrade the ignition.

Honestly, you would have done well to measure the voltage at the coils prior to performing the mod to ensure it was needed and you don't have other problems. After performing the mod, the voltage should be checked again. Use a multimeter to ensure you are getting a bit over 12VDC with bike not running. If you hear the relay click when you turn the key on, the relay is working and if the bike runs, the upgrade was done correctly but it won't substitute for not doing other maintenance items.

I made a small modification to the system. I wired a toggle switch between the battery power wire and the coil feed wire, that is normally in the off position to use in case the relay ever crapped the bed or the battery died. In either case you just flip the switch on and it bypasses the relay so the charging voltage when push or kick starting the bike goes all to the coils and doesn't have to power the relay too. May be just my over engineering though.:woohoo:
I just mounted the switch on a plate I made under the seat so it's out of the way and can't be turned on without lifting the seat with the key lock.
Ride safe,
Les

Milkman a good mod, however, we must be careful not to put too many switches, connectors into the circuit, as it will defeat our intial purpose of by-passing the ignition/kill switches to avoid voltage drop!

Without Milkman's "extra" mod, is there any problem clutch starting down a hill with a flat battery? Will the alternator supply enough to pull the relay on? I would presume so!

Anyone encountered any disadvantage with the main "Relay- Coil Mod"?

RegardZ.

wiredgeorge wrote:

Honestly, you would have done well to measure the voltage at the coils prior to performing the mod to ensure it was needed and you don't have other problems. After performing the mod, the voltage should be checked again. Use a multimeter to ensure you are getting a bit over 12VDC with bike not running. If you hear the relay click when you turn the key on, the relay is working and if the bike runs, the upgrade was done correctly but it won't substitute for not doing other maintenance items.

Yeah I didn't measure it before, but I assumed from everyone always recommending that it be done that it woudl always be a benefit to get a fatter spark at the plugs. Since the spark seemed weak on mine I figured that I'd go ahead.

You're right though, I do plan on making sure everything else is working correctly and no it's not a substitute for good maintenance practice.