How does the Starer Relay coil get power?

[jim]

Hi Geoff,

Following your post, I think I understand this now (hopefully)

So this relay(9) acts as a DPST (Double Pole Single Throw) relay - 2 independent circuits switching simultaneously when the coil is energised.



Usually a DPST relay would have 6 terminals (2 for the coil and 2 each for each independent circuit) .What Yamaha appear to have done is connect 2 of the circuit terminals internally in the relay body (to both sides of the coil (12v & path to ground through Neutral switch).

This is fair enough, but it sure as hell is confusing, as on the circuit diagram it looks just like an SPST relay. A note on the circuit diagram from Yamaha would have been nice.

Anyhow, thank f**k - It was doing my head in!!

If anyone wants to replace this relay, without paying big for an OEM part, any low power DPST relay should do. Just bridge the coil terminals to the circuit terminals externally.

Thanks to Geoff and Mezo.

Onto the Neutral Relay now,!

I may need more help Geoff.

[jim]

Hi Charlie,

I am just getting into my bikes wiring, so I can't honestly tell you how it is wired yet - it's a mess for sure.

Years ago I employed your minimalist approach to wiring on my Norton Commando. No indicators. Wire to coils from battery through cut-out switch. Wire from coils to distributor. Foot brake wired up. No headlight - just rode during the daylight.

What I know about the 3AJ wiring (limited) I got from this forum. Posts from GeoffD and Motorang very good.

As far as I can see, the 3AJ needs very little wiring as a minimum. You don't need a clutch switch, sidestand switch or even a neutral relay(mine is running without one). The fundamentals are getting power to the starter motor to get going, and shutting down the CDI when you want to stop the engine.

Check this post out from Motorang. viewtopic.php?p=33034#p33034

Only really a couple of wires on the CDI to consider to enable/disable the sparking.

Cheers Jim

[jim]

Charlie,

I had another look at Motorang's post and noticed something that I hadn't before:

There is a Diode in the circuit for Relay 9

This prompted me to have another look, and redraw the circuit for both relay 8 and 9 below (Basically Motorang's)

So I got it wrong. It looks like both relays are Single Pole Single Throw (SPST) and are wired internally as shown. I need to confirm this when I get my multi-meter back from my mate.

It works as follows.

Relay 9 will be energised if Ignition switched on, Engine Run switch operated, and either Bike in Neutral (via neutral switch)or Clutch Lever operated. The diode is to stop the Neutral light coming on every time you operate the clutch. The bike will start if Engine Start button is pressed and Blue/Yellow wire at CDI unit is grounded. The CDI will only produce pulses to the Coil if this wire is grounded.

The CDI unit Blue/Yellow wire is grounded if either the Sidestand is up, or the bike is in neutral.

If the Sidestand is down, and the bike is in Gear the CDI Blue/Yellow wire has no path to ground under any circumstances, and the bike will not start even with the clutch pulled in.

If the sidestand is up, the bike is in gear and the clutch operated the bike can start.

The way my bike has been wired is that as long as the Engine run switch is on the CDI can spark. I need to check, but in all likelihood Blue/Yellow goes straight to ground through the Run switch.

I have no clutch switch - the main disadvantage here is that the bike will not start unless it is Neutral. A disadvantage in my opinion if you stall on a hill, and have difficulty finding neutral.

The two relays (8 and 9) could probably be replaced by one Double Pole Single Throw relay.

The internal diode in Relay 9 could be configured as an external diode connected to the blue wire, so still avoiding expensive OEM parts.

Again, credit to Motorang for this...........I hope I got it right this time.

[charliext1vj]

Jim many thanks for this and I will definitely use it - it makes sense to me......just to say something to show I have tried to understand it! I would think the diode (apart from neutral light bit) is more about stopping that relay getting a false feed in the reverse circuit.. Thanks again interesting read. Charlie