Power to neutral safety switch

Hi, can someone tell me if there is supposed to be power coming from the neutral safety relay to the neutral safety switch or does it act like a ground and how to test the diode block. It's a 82 xj650rj . Thanks

 

By neutral safety relay do you mean side stand relay?

Normally, the neutral safety switch simply grounds the wire to chassis ground while in neutral. So yes when not in neutral it should float high indicating 12v to chassis on the switch wire if the associated wiring is OK and the other components are functioning. Typically, three paths are provided, one through the neutral bulb, one through the starting circuit cutoff relay, and one through the side stand relay. When the bike is in neutral, the switch closes providing a current path for energizing the starting circuit cutoff relay, the side stand relay, and illuminating the neutral bulb.

Perhaps if you would explain what your bike is not doing it would help.

Also, the diode block if known good can easily be evaluated with a meter to determine the internals. Unfortunately, I have the XJ750, which is a different part number for the diode block. I attached a PDF file for that model, which does cross to quite of few others. Anyway, you can evaluate yours using the same method. Per Len - ye who knows all, they seldom fail. Perhaps one of the best tests is the sniff test.... is it burnt?

 

What I am trying to do is get all the safety features enabled. Temporarily I've bypassed the side stand switch.The neutral safety switch has been removed from the crankcase for replacement. Previously when I grounded the SB wire coming from starting circuit cutoff relay (that should go to neutral switch), the neutral light would light up and you could start in gear. When I ground it now the bike will start, but no neutral light. I've checked the bulb and it's ok. As you stated there seems to be the three paths switch, neutral light and diode. I tried following the Haynes manual for checking the diode and I do get around 8 ohms when checking the BR to G, but in testing the rest of the circuits in the diode I get no results of any kind. Now the diode looks healthy, no smell no burn marks. Since the clutch lever switch works (which is connected to the diode) it makes me wonder if I'm doing something wrong. So I'll be ordering the neutral safety switch today and perhaps I'll get better results once it's installed. Thank you for your reply.

 

Good to hear you are restoring the safety circuit - I am a believer in as humans we all make mistakes, and just one time with that side stand down can cause a catastrophic event.
As for not getting the correct readings, if you are using a DMM, it must have a selection for testing diodes.



In the other settings for continuity, the DMM will not provide enough voltage to forward bias the diode, so you will read open in both directions.

If you have the correct meter and still want to test the diode block, start with the positive lead on one pin, touch the negative on the remaining pins making note of the readings. Move to the next pin with the positive lead, and touch the remaining pins with the negative lead. Do this for all the pins and then repeat by reversing the leads. From the readings you get, you can map out what is inside the diode. Hopefully, the Haynes manual tells you what to expect, otherwise it is going to be difficult after mapping it to determine if there is a fault.

Some diode blocks do have a resistor inside, which would account for the 8 ohm reading you mentioned.

Also from your previous post "Neutral safety light stays on"

"Yep.I decided to trace that light blue wire all the way to the headlamp. Took apart the main harness and found he'd grounded it at the frame and bypass the safety relay, connected the 2 light blue wires from the diode and neutral light then back to the relay. So I severed the connection at the Y and the neutral light is out now and the bike will only start if the clutch is depressed, so at least that part of the safety switch is working."

Perhaps the "Y" was not a previous PO mod. Since the sky blue wire goes several places, Yamaha would have had to splice it somewhere. It would also seem strange that a previous PO would dig into the harness to defeat the neutral safety when they could have just grounded it at a much easier location. If it was truly grounded physically to the frame, yea that would be an issue.

 

Two things: The Haynes is not the best reference here; it refers to the "Euro" 650 which doesn't have the same safety circuit from what I can tell. The FSM with all its foibles goes out of its way to explain the safety circuit on the 650R; PM me with an email address and I will send you a scan.

DO NOT assume that the diode block is the same from model to model; and remember that the diodes within belong to various different circuits on the bike. Plus, as above, unless obviously burnt (usually due to human intervention) they rarely fail.