The circuit diagram below was photoshopped from several files from this forum (thanks Mezo). Its a big image 10MB and can be downloaded directly from http://easyonlineweb.co.uk/images/3AJ%2 ... iagram.jpg if anyone wants to.

I can't figure out where the starter relay (10) coil gets a positive supply from. I can see that the bottom end of the coil is connected to earth through the engine stop switch (1) and start button (2). The top end of the coil (where we need to get power to) goes through the starting circuit cutoff relay (9) then through the clutch switch (35) to the CDI (5) on the blue wire.

I thought that the CDI was powered from the alternator via the Red and Brown wires, and has no connection to the battery. So how can it be providing power when the engine is not running??

The starting circuit cutoff relay operates as long as the ignition switch is on, and the bike is in neutral (switch 7) - so no problem there.

But I just can't figure out how the positive supply to operate the starter relay coil gets there. This is driving me crazy!! Please help

I`m obviously not understanding the question properly.

Its getting its power from the battery (next door) No12

EDIT: I`m not taking the piss jim, it is getting its power from next door (follow the red wire) are you asking how the coil is energised? how its switched or activated?

Mezo.

Hi Mezo,

Yes, It's how the coil gets power to energise/activate the relay (10). I can see how the coil is connected to ground through the run/start buttons, but not how it's getting its positive supply .

Thanks Jim

As Mezo said, the relay get it's main feed from the battery... large red wire...

To energise the relay it has an ignition feed coming from cut off relay... red and white wire

The blue and white wire goes to kill switch/starter button

Hi Geoff,

Yes, I can see that the 12V must come from the red/white wire from the cutout relay (9), but if you follow that wire through the other side of the relay it comes out as a black/yellow wire which then goes through the clutch switch and from there into the CDI unit.

So unless the CDI unit is supplying the 12V, where is it coming from?
Jim

Geoff, Mezo

It's difficult to explain this in words so I've added pic below:

Looking for 12V across positions 1 and 2 for starter relay(10) to energise.

Position 1 has a path to ground through engine run switch and start button.

Position 2 needs 12V supply, and goes through starting circuit cut-off relay(9) on red/white wire and out other side at position 3 on black/yellow wire. Goes through clutch switch at position 4 and then to CDI at position 5.

I thought that CDI had no power to it unless engine was running, and power coming from alternator. And why is the clutch switch involved anyway. I'm just not getting it!

jim wrote: Thu Aug 27, 2020 3:48 am Hi Geoff,

Yes, I can see that the 12V must come from the red/white wire from the cutout relay (9), but if you follow that wire through the other side of the relay it comes out as a black/yellow wire which then goes through the clutch switch and from there into the CDI unit.

So unless the CDI unit is supplying the 12V, where is it coming from?
Jim

Jim you're not getting it.....

The ignition feed to starter relay comes from no.9... yes... it does NOT come out the other side as a black and yellow wire... they are 2 separate wires doing different things....

No.9 is a relay, it has live (brown) wire feeding it.... it distributes 12v to various parts of the system depending on the state of the 1. Neutral switch 2. Sidestand switch 3. Clutch switch..
ie if the bike is in neutral with the sidestand up... the relay will provide power to the starter relay, cdi, neutral light, etc... if the bike is in gear the bike won't start unless the clutch is pulled in...
Similarly if you have the sidestand down and you pull the clutch in and engage a gear, the engine will cut out.... this is all operated by the starting circuit cut off relay

The black and yellow wire isn't connected to the red and white wire, they are both separate ignition feeds

Hi Geoff, thanks for taking the time to help me out.

My bike has no clutch switch, neutral relay or sidestand switch - so I can't do much with the multi-meter to check against the circuit diagram. It wasn't even protected with a fuse when I got it - is now!

But your dead right - I'm not getting it!

I understand that there are 2 different systems/circuits at play here.
One for starting the engine, by allowing power to the starter solenoid and one for stopping the engine, by the CDI stopping sparking (sidestand switch/neutral switch).

I will rewire the bike properly over winter, with clutch switch, neutral relay and sidestand switch - but will need to understand how it is meant to work.

Maybe I'm not understanding how the relay connections are shown on the diagram.

I m reading the diagram as follows for relay 9.
A simple Single Pole Single Throw relay (no internal wiring not shown on diagram) - 4 wires (2 for coil and 2 for contacts). When relay coil is energised the 2 contacts are connected.
Brown wire - relay coil - 12v from ignition switch
Blue wire - relay coil - connection to ground through neutral switch.
Red/White wire - relay contact.
Black/Yellow wire - relay contact.

Is this correct?

If there were internal contacts inside the relay it would make sense that the Brown wire and Red/White wires be connected when the relay was energised and similarly for the Blue and Black/Yellow wires.

Is that it? Is that how this relay is actually wired?

Please tell me that is where I have gone wrong

Jim,
I am looking at starting my next rebuild 3TB engine in a 1VJ Frame. (For those whom like originality stop reading now!) I plan to minimise the wiring to its simplest form with lights, battery and Electric starter - my aim is to run as basic as I can - I have so many spares and will have some fun considerations along the way e.g. I have all the Xt swinging arms, different forks and braking et al.

I am wondering if you can provide a basic wiring schematic of what you have or a number of pics? In turn might help me/others work out your issue? Sometimes wiring diagrams can through you off and it easier just doing dot to dot with colours on plain paper.

Either way Good luck Charlie