Interchangeable relays?

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kyleblaqk
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Interchangeable relays?

Post by kyleblaqk » Mon Dec 19, 2022 12:17 am

Hello!

After just a few days of owning my TRX (loved it for the first 80 miles I did manage to ride) it's decided not to start. Not in the sense that it wont fire, more so that pressing the starter button yields absolutely no action. Testing the voltage on the button reads 0v, and jumping the 4EP 81950-00 relay under the seat makes the button spring into life. Upon testing the relay as per the manual, it seems faulty.

So my question is, lovely people, will a relay from another Yamaha say the 3EN-81950-00 from an FZS600 work the same? I'm struggling to find a direct replacement from the UK - only Lithuania and Germany pop up. Alternatively, if anyone has one for sale please let me know!

I'm hoping this will fix my issue... been a bloody nightmare tracking it down. And I know the weather is crap at the moment, but it's still bugging me that the bike sat in my garage is no more than a pretty ornament at the moment!

Thanks in advance!

Kyle

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dicky
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Re: Interchangeable relays?

Post by dicky » Mon Dec 19, 2022 6:45 am

It's unusual for this relay to fail, but not impossible.
I'd test everything else thoroughly before looking to buy a new one.
Even if you test the relay according to the manual it can still be faulty, there is a circuit board inside the relay housing with the logic diodes on it.
For the relay to activate either the neutral switch connection must be earthed, or the clutch & side stand connections must be earthed. (or both, for the full belt & braces experience)
If I had to test it, I'd check all of those switches first, all the way to the relay socket just to make sure.
To test the relay I'd do the following:
Measure the coil resistance between R/B & B/Y. It should be around 220 Ohms. Doesn't matter what direction, same same.
Using the Diode function on a multimeter, test between B/Y and Lg, L/Y and Lg, and Sb and Lg. Measure each one in both directions. You should find that with the black test lead on Lg the tester will beep for each one.
If that all works, connect 12v across the R/B & B/Y connection and measure the Ohms across both L/W connections. It should be open circuit with 0v and close to zero with 12v.
If you pull the relay out, looking down at the base the pins are:
|nc|nc |__|LW|RB|sB|
|nc|LW|BY|Lg|LY |nc|

If you do need a replacement, try looking at the service manual for newer vintage bikes and see if the schematic shows the same configuration of relay coil and diodes.
Even if you find one that's wired up differently you could pull the plug wires out and swap them around.
dicky
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Re: Interchangeable relays?

Post by kyleblaqk » Mon Dec 19, 2022 12:02 pm

Hi Dicky! Thanks for getting in touch so quickly. So I've ran the first lot of tests you recommended - with the relay off the bike. Firstly, I got 210 Ohms between R/B & B/Y which I'm guessing is moreorless on the money. The check between B/Y and Lg was fine, but I got nothing between L/Y and Lg, and Sb and Lg. I'll connect power now and give the next check a whirl, but I'm guessing from this, the relay isn't operating as it should?

That's good advice about the relays and swapping the wires. Manuals are easily enough to get hold of with the schematics in, so that might be worth a shot.

Thanks again!

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Re: Interchangeable relays?

Post by kyleblaqk » Mon Dec 19, 2022 12:21 pm

Hello, just a quick update. I just ran power to the terminals you recommended and it clicked (never heard that before). Then the connection between the 2 L/Ws completed... so given all that, and what I said in my previous reply... what on earth does all that mean?

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Re: Interchangeable relays?

Post by Tarwetijger » Mon Dec 19, 2022 1:48 pm

kyleblaqk wrote:Hello, just a quick update. I just ran power to the terminals you recommended and it clicked (never heard that before). 8<
So does it start now?
dicky wrote:It's unusual for this relay to fail, but not impossible.
It is the starter relay, right?
I had to replace one once.

CMSNL states: "This product fits to 144 models."
So that's quite a lot to widen your search. At least the one from TDM850 is the same.

Here in NL is one available:
https://www.baboon.eu/nl/onderdeel/yama ... 0001380224
Not UK based but they are used to international postage.

Oh here's another one
https://www.svolta.nl/fz-400-fazer-4yr- ... fazer.html

The starter relay is not a complex piece of electronics, I think one from another bike or an universal one will work just as fine.

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Re: Interchangeable relays?

Post by kyleblaqk » Mon Dec 19, 2022 2:25 pm

Hello!

No it doesn't start still. I was testing it off the bike, just hooking power up to the terminals (recommended by Dicky) and the relay clicked. Reconnecting the plug to the relay and still not starting/starter spinning.

It's not the relay with the 2 big wires and fuses in, it's the 4EP 81950 00 as you shared below :) And thank you by the way for sending those through, looks like there's plenty of options!

I'm really at a loss with this bike at the moment. I just cannot get the starter button to do anything! #-o

A few facts about the working order of the bike, just in case they paint a picture:
- It used to start and run perfectly; pressing the button one day did nothing, so I wiggled the key and eventually the button worked. This trick worked twice and never again.
- the neutral light is on
- bridging the starter solenoid with an old spanner spins up the starter motor
- all the fuses are fine
- the main earth on the bike is in great condition
- all the lights work
- there is voltage on the starter button when I touch the multimeter to the terminals and the battery, pressing the switch puts voltage on the other terminal too
- when I got the bike to crank, by jumping the starter cable (blue & white) in the relay (4EP8915000); I did find with this that the killswitch did nothing, ie. I could flick it and the button still worked, but I'm guessing this is because I bypassed the relay essentially.
- I put the multimeter between one of the terminals on the killswitch, and the corresponding terminal on the relay, and it reads very high resistance (again, just guessing here)

And that's about the lot. I've been at it for over a week now, gone as far as to take apart the starter motor, clean it and rebuild it... :?

Hopefully, you'll read this and immediately see my problem 8-[

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Re: Interchangeable relays?

Post by Tarwetijger » Mon Dec 19, 2022 3:51 pm

Oh I didnt understand correctly, so it's not the starter relay itself but the 'safety check' relay hence Dicky saying:
"For the relay to activate either the neutral switch connection must be earthed, or the clutch & side stand connections must be earthed. (or both, for the full belt & braces experience)"

You said the neutral ligt is on, have you checked the cluth and side stand switch?
Especially the sidestand switch is known to be faulty.

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Re: Interchangeable relays?

Post by kyleblaqk » Mon Dec 19, 2022 4:12 pm

That's right.

I couldn't figure out where the clutch switch goes in order to check it, and as for the side stand switch, I wasn't sure how to check that either but I at least know where the plug is for that.

Apologies for my incompetence... How would I check that the switch is earthed? Thank you in advance

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Re: Interchangeable relays?

Post by Tarwetijger » Mon Dec 19, 2022 4:28 pm

kyleblaqk wrote:That's right.

I couldn't figure out where the clutch switch goes in order to check it, and as for the side stand switch, I wasn't sure how to check that either but I at least know where the plug is for that.

Apologies for my incompetence... How would I check that the switch is earthed? Thank you in advance
The switch for the clutch is right behind the clutch lever. And the sidestand switch is sitting behind the sidestand.
You didn't see that one coming, did you? :P
But seriously, you could just check (with multimeter) if both switches change anything if you grab the lever or kick the sidestand out.
For example if the sidestand switch doesn't change if the stand is in or out, then you know that might be the problem.

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Re: Interchangeable relays?

Post by kyleblaqk » Mon Dec 19, 2022 4:47 pm

:D excellent!

Well I've tested the Sidestand switch by sticking the multimeter on each of the prongs, kicking it up and back down again and it opens and closes the circuit (though the resistance on the meter is pretty high when the circuits closed). As for the clutch switch, I see it (there's a start right) but how do I test it with the meter? Can I do it at the switch or do I do it where it's cables lead? (And where is that)...

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Re: Interchangeable relays?

Post by dicky » Mon Dec 19, 2022 10:36 pm

The diodes inside the relay may be faulty, meaning that even if the clutch and side stand switches are working, they will not allow the relay to active.
I'd keep checking the switches first, then the wiring from the switches back to the relay plug.
The clutch switch is easy to remove, you can test it directly at the switch.
dicky
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Re: Interchangeable relays?

Post by Tarwetijger » Thu Dec 22, 2022 11:37 am

kyleblaqk wrote::D excellent!

Well I've tested the Sidestand switch by sticking the multimeter on each of the prongs, kicking it up and back down again and it opens and closes the circuit (though the resistance on the meter is pretty high when the circuits closed). As for the clutch switch, I see it (there's a start right :lol: ) but how do I test it with the meter? Can I do it at the switch or do I do it where it's cables lead? (And where is that)...
The cable goes somewhere under the yoke through the frame and under the tank and airbox.
So, not very convinient. :roll:

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Re: Interchangeable relays?

Post by dicky » Thu Dec 22, 2022 11:01 pm

The starting circuit is a bit of a nightmare to follow. The diagram on page 8-12 of the service manual shows the flow chart view, but it's a bit more complicated when you get to the physical wiring.
You can test the clutch switch at the relay connector by measuring across B/Y and L/Y. It should be close to 0 Ohms when you pull the clutch lever in.
The side stand switch is L/Y at the relay connector, measuring from L/Y to earth will show the switch resistance. It should be close to 0 Ohms with the stand up.
The clutch switch and side stand switch work in series, so to measure that you need the side stand up and the clutch lever pulled in while measuring from B/Y to earth. Again, it should be close to 0 Ohms.
You mentioned that the side stand switch resistance was 'pretty high'. How high, exactly? Try giving the switch a squirt with electrical contact cleaner.
If the switch in the side stand is dirty and not making good contact then this may be the cause of the problem, but only if you try to start the bike in gear. If it's in neutral then the clutch and side stand switches have no effect.
(which I see that you did mention in your earlier post, the bike was in neutral but wouldn't start, so forget about most of what I've said)
Connecting B/Y to earth made the relay click, so that shows the relay does actually work.
You should also be able to activate the relay by connecting Lg to earth. If that doesn't work then the internal diode in the relay is probably dead (but you tested it and said it was OK, curious). I think you can cut the relay housing open and get into the components, but that might be a last resort.
Connecting B/Y or Lg to earth should let you start the bike with the starter switch.
You also mentioned the kill switch, this is in series with the battery supply to the relay (as well as the ignition coils), so it should be close to 0 Ohms when in Run position and definitely should prevent the relay from operating when in Stop position.
Measure the resistance from the positive terminal of the battery to the R/B lead of the relay socket, with the Key switch ON and Kill switch to Run. It should be close to 0 Ohms, if not try giving the Kill switch a squirt with electrical contact cleaner.
Does any of the wiring look like it has been altered?
dicky
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Re: Interchangeable relays?

Post by dicky » Fri Dec 23, 2022 2:08 am

The more I think about this the more it sounds like it's just the kill switch.
dicky
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Re: Interchangeable relays?

Post by davamb » Mon Dec 26, 2022 7:42 pm

Have you tried pushing the start button really hard?
Ride Well!
Cheers, Dave.

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