Neutral light oddity

Picked up another '82 650 over the weekend. Less than 6000 miles and in really great shape. I'll post some photos after some cleanup.

One issue is the neutral light. It works correctly when in neutral, but then also comes on whenever the clutch switch is pulled when in gear. I'm assuming this is a diode, but would that be in the diode block, or possibly the diode in the neutral relay switch itself?

 

My guess is it has an led bulb for the neutral indicator - there is just enough voltage generated by the starter cutoff relay coil that toggles with closing and opening the clutch switch

 

I guess you could argue that it is in Neutral when the clutch is pulled in

 

Piecing together some wiring diagrams, it seems like this would happen if the diode in the starting circuit relay was burnt, allowing current in either direction. Normally I'd figure there had been some wiring hack job done, but this bike is so original and untouched so far. It will be me that probably ends up doing the hack job!

 

You may be right on that, this diagram shows that a little clearer:



I wouldn't "hack it up" if original. Yamaha's harness is pretty simple, works well, and easy to troubleshoot. The FSM has really good troubleshooting steps for the electrical. Most hacked harnesses are usually the result of someone that won't take the time to methodically troubleshoot things. I was young once too......

 

Swapped out the neutral relay this evening and that fixed it, so no hacking required. Even finished the carb rebuild, set floats and got it fired up. More to come!

 

I've just had this issue and the starter circuit relay was the main suspect, now pretty much confirmed. My clutch switch has been bypassed so the neutral light is on all the time, but glows very slightly brighter when the bike is really in neutral. If I can't get the relay apart I'll try inserting a separate diode in the loom, near the relay.