Black / Yellow Wire CDI to PV

[element137]

Hi all, as part of my no spark woes - (on a separate thread)  - apologies if this a dumb question - I been going through and checking as many wires/connections on the CDI - on the drawing I have, the loom takes two black and yellow wires- one from the CDI to the PV controller (Black Yellow to Black Yellow on the loom)  - and one from the PV controller to the servo -Black White from PV Controller to Black Yellow on the Loom ) ( see pic below )  I am using a brand new replacement aftermarket loom - and testing continuity I have found that the loom is reversing these wires ? ie, the wire from CDI is going to the Servo connection, and the other Black yellow from the PV controller is going to the CDI - question is - doe this make any difference ? - PV cycle OK on IGN on - but as I not had the bike started yet - I don't know if they are behaving correctly Versus revs ? - 

CDI PV Control Wiring
 

[midlifecrisisrd]

As long as both black and yellow wires are connected together it doesn't matter

If you have 2 separate black/yellow wires without a connection between them then that's a different issue

Steve

[element137]

Thanks Steve -

[element137]

Looking at Haynes manual its different to the drawing I have ( above )- so I don't know which one is right - has anyone got a Yamaha workshop manual wiring diagram I can reference to please ?

[element137]

Also - I think from my pretty basic multimeter testing - must be two separate wires as continuity only on two connections - I would assume that if both wires were connected then get continuity anywhere on that black / yellow circuit ? - although clearly - I have not much knowledge in electrics -

see pic below -

[midlifecrisisrd]

Hang on, I didn't think the black/yellow wire went direct to the servo 🤔

Steve

[midlifecrisisrd]

Is it not usually a connection within the pv controller?

Don't even know if it's the same function or just same colour

Steve

[JonW]

The BY does travel the whole Pv circuit - from CDI to PV controller and then on to the servo.

The way i think it works is that the CDI sends on the revs info to the PV controller which sends on to the servo motor. We know its revs as some have used it for tacho connection.

I suggest that the continuity between the connectors in the loom will only be between wired pairs as you probably wont pass current though the boxes. ie CDI connector to/from pv controller connector and pv controller connector to/from servo connector. I would not expect continuity from CDI connector to/from servo connector as it would need to pass through the pv controller... assuming its connected. But it might...

FYI On a ypvs loom the pv controller to/from servo connector is actually a extra small loom and can be split out from the main loom. The wires only go between those connectors and are not soldered to anything else. It looks like an afterthought when you see it.

If you undo the boxes and the connectors and test the runs, you should have continuity between the 2 runs (1, servo<>PV ctrl and 2, PV ctrol<>CDI). If you dont have that then the problem is in the loom, there is a break. If these runs have continuity then its from the loom to the boxes or the boxes themselves.

HTH, my brain hurts a bit thinking about it. This wiring diagram you have isnt ideal. See if you can find a real LC2 manual, this one is ok on Xavier's site:

rd350lc.net/WM31K-8.pdf

you can see the spots to see where wires are connected internally on this, otherwise they are not. Its not obvious in the colour one etc.

[JonW]

Also, test the wires if you dont get a connection, not just touching the connector in the block. Sometimes the connection is broken at the wire/pin or has not made a good connection at the factory.

Also, check they are seated correctly if the loom tests ok and test across the connector on the wires.

To test from the wires themselves you can put a pin through the wire plastic coating to get to the copper inside.

[darboots]

If it helps, Kojacat sell A3 colour wiring diagrams for various bikes. It's been a godsend for me in the garage.

kojaycat.co.uk/epages/950000457.sf/en_GB/?ObjectPath=/Shops/950000457/Categories/Motorcycle_Wiring_Diagrams/Yamaha/RD250LC_RD350LC_Wiring_Diagrams

[element137]

Thanks for the advice all - the diagram i have used is a Kojaycat one - problem is I only have that and Haynes drawings to reference to and they are different - Haynes shows the actual wiring to be correct - the KJC colour drawing is different - (as above pics) - so I don't know which one is correct -
see Haynes drwg below- its not that clear to read - but this show the current wiring on the loom I have to be correct -

[JonW]

The haynes looks just like my LC2 diagram i checked the other day for you, mine was from OEM Yamaha manual.

[element137]

Jun 16, 2023 14:16:18 GMT 1 JonW said:

The BY does travel the whole Pv circuit - from CDI to PV controller and then on to the servo.

The way i think it works is that the CDI sends on the revs info to the PV controller which sends on to the servo motor. We know its revs as some have used it for tacho connection.

I suggest that the continuity between the connectors in the loom will only be between wired pairs as you probably wont pass current though the boxes. ie CDI connector to/from pv controller connector and pv controller connector to/from servo connector. I would not expect continuity from CDI connector to/from servo connector as it would need to pass through the pv controller... assuming its connected. But it might...

FYI On a ypvs loom the pv controller to/from servo connector is actually a extra small loom and can be split out from the main loom. The wires only go between those connectors and are not soldered to anything else. It looks like an afterthought when you see it.

If you undo the boxes and the connectors and test the runs, you should have continuity between the 2 runs (1, servo<>PV ctrl and 2, PV ctrol<>CDI). If you dont have that then the problem is in the loom, there is a break. If these runs have continuity then its from the loom to the boxes or the boxes themselves.

HTH, my brain hurts a bit thinking about it. This wiring diagram you have isnt ideal. See if you can find a real LC2 manual, this one is ok on Xavier's site:

rd350lc.net/WM31K-8.pdf

you can see the spots to see where wires are connected internally on this, otherwise they are not. Its not obvious in the colour one etc.

Thanks Jon - that link to xaviers site - the drawing there match's the Haynes one - so I am going to assume the current loom is correct -and the  KJC one I have is in-correct -  I guess I will find out once I get it running - thanks to all who chipped in with advice - greatly appreciated - 

[JonW]

yep see how it runs and if not working then try swapping those wires between the two plugs. Its possible that they could have been swapped by accident when the loom was made, they are the same colour after all.