Neutral light not triggering

Hey guys,

I'm having some issues with the neutral light on my 1980 KZ750 and wondering if anybody has some ideas.

I started the bike in the spring, and kicked it into gear (on the centrestand) to make sure the new clutch cable and shift lever worked. It didn't seem to want to go back into neutral, which had me worried, until I realized I could find neutral by trial and error, the light wasn't just going on.

I think the light was working before I shifted it out of neutral. When I take off the neutral switch and touch the end to the engine case, the light comes on. When I bypass the neutral switch by touching a piece of wire between the wire going to the switch, and inside the hole where the switch screws in, the light comes on.

Looking at the manual, it could be that when the bike is in neutral, the shift drum isn't touching the neutral switch, but I'm reluctant to start going that deep, at least unless it seems likely that's the culprit. Has anybody run into something like this before? Thanks for any suggestions!

you can download a copy of the shop manualmanual here
kz.bike-night.com/media/GPz750-full.pdf
There a testing procedure for the neutral switch on page 238 or 239.

Neutral switches do fail. When I bought my 1980 750/4 years ago the neural switch was dead and I replaced it with one from Z1Enterprises.com
www.z1enterprises.com/ItemDetails.aspx?i...saki&item=13151-1080
They are cheap and easy to replace.
Good luck

Thanks for the manual link; I'll check out that testing procedure. I thought it was the switch originally since it didn't test with a multimeter, but today I cleaned it a bit and it seemed to work. In any case I should find out soon.

Also I hadn't seen a neutral switch on Z1Enterprises - that'll save me a few bucks and having to do a separate order.

Here's a topic - I haven't done anything about it yet. :blush:
WGCarbs - Vintage Bike Forum - Flickering neutral light

Just got the new neutral switch and installed it (Friday night repairs by flashlight for the win) - didn't work. My guess is I'll need to remove the sprocket and everything to get behind where the switch is installed, and see what's going on back there.

I noticed a bit of a description in that thread you posted, Martin - I don't suppose you've had a look on your bike since you posted that? Or anybody else have particular advice before I start digging behind the sprocket?

I didn't get the chance to dig into it this last weekend (looks like an impact wrench may be the best way to take off that front sprocket bolt).

From what I can see though, the shift drum pin plate that the neutral switch contacts has a "C"-shaped black bit on it, where the opening faces to the front of the bike when in neutral. It looks like rubber so I'm thinking the neutral switch is supposed to contact the opening when in neutral to ground out and activate the light. However, when I look into the neutral switch hole, I don't see the gap, so maybe the plate got turned so the right part isn't behind the switch when in neutral?

Or it could be to do with the long pin behind the plate not making good contact for some reason?

Of course, this is probably more of a transmission topic than an electrical one . . .

I checked today and when I attached a wire to the neutral switch lead and touched the other end to the metal on the shift drum pin plate (beside the rubber bit, not where the switch was contacting - hopefully not touching other metal that would ground it), the light came on. So the plate itself should be grounded, and maybe just got out of position somehow. That'd be great as I'm hoping the answer doesn't lie too deep in the bike . . .