FZRSupport: the FZROnline Archive

My haynes wiring diagram says the FZR has a speed sensor on the white/green wire that comes off of the turn signal relay. I am currently wiring around that and replacing it with a two prong cheap flasher because that is how the YZF600 is set up and I have YZF600 switches now.

There were cancellation issues before with the YZF600 switches when the turn signal was engaged, I'm bypassing that. Can someone tell me more about this speed sensor/speed switch?? I know it's not a "speed sensor" as my haynes manual lists it in the wiring diagram, unless it senses the speed of the cable as it spins and that signal is sent to the speedo needle.

I have an old set of broken gauges I can rip apart and look at internally, I forgot I had those, I'll rip them apart tomorrow so I'll know more about this "sensor".

So why does this white/green wire come off of the flasher relay and not off of one of the fused wires directly?

Is it supposed to be only a hot wire that powers the sensor so it can sense the speed of the cable spinning?

And another thing, does the speedo needle work when the bike is off and you are coasting?

If the speed sensor tells the speedo needle what speed to show, then when there is no power to it (when the relay is off or the wire is disconnected) we shouldn't get any reading. For some reason I always thought it was purely mechanical since there is a physical cable from the wheel and not an actual "speed sensor" in the trans case.

Can I jumper the white/green wire off of the brown wire that powers all of the accessory things on the bike?

That way the sensor gets power..I might just try it anyway, or dissect an FZR flasher relay just to see the white/green wire inside, unless the internals are encased in that electronic sealant stuff. I still have a full parts bike and two spare harnesses to pull anything from I need if I fry anything.

Match,
I cannot say for the FZR series of bikes BUT on previous Yamaha's that "speed sensor" was a timing circuit to shut off the indicators after a time . This time appeared to vary with road speed or may be revs based on I would assume (never that smart ) how much voltage was going thro the circuit for that given rev range to trip a timing circuit.

As you say the whole assembly was potted in synth, rubber and had just the one wire going in and the case acted as ground.

I would try and remove the "rubber" with some kind of solvent if you are going to explore the innards trouble is most solvent will "eat" capacitor labels & paint on resistors.

but Happy tinkering and let us know what you find...........

I dissected the broken speedo..yeah, it's a sensor of some sort. I tried testing the resistance of it with a steady speed created by my drill spinning the speedo gear, and the resistance values the sensor was showing were very random, it jumped from 30 to 0 to 180 ohms and the readings were not regular or steady at all, I was expecting the resistance to increase or decrease with the speed, that wasn't the case. It didn't seem like it was a series of on's and off's either. On full speed with my drill the resistance stopped jumping randomly and showed no resistance (at 30 mph speed) and with my drill on the lowest speed the resistance was jumping around to everything between 30 and 180, and would sometimes stay blank(drill very slow, it showed 0 mph on the gauge).

So I don't know either, it's not a regular reading increasing or decreasing with speed, and it's not a series of on's and off's. Maybe the functionality is different when the gauge is showing higher speeds. So I conclude that disconnecting the white/green wire won't affect the bike in any way since I have replaced the flasher with a generic one, and I now have YZF600 switches. Speedo works with no power at all, and the sensor doesn't tie in to the tci box. And considering the wire is on the turn signal flasher box, it must have something to do with what you said.

the only green on my wiring diagram is the right turn signal, there is green/red that is for the tach, and green/yellow for the front brake switch, but none of them go to the tci. The white/green goes straight to the flasher, and none of the other wires from the flasher touch the tci, with the exception of ground of course.

oh, are you talking about the digital gauge mod? I'm not doing that upgrade. I had an issue with the auto-cancellation feature that is built in to the flasher since I upgraded my stock switches to YZF600 and those switches don't have the auto-cancel function, so I took out the stock flasher and wired in a generic one, ignored the white/green and yellow/red wires coming off of the flasher and was wondering if the speed sensor (white/green) would actually cause gauge problems since I can't ride the bike right now and I can't verify that by riding it. Now since I've dissected my old broken gauges, I'm confident that there will be no problem with the speedo when doing this. I'll post a "how to" on the switch mod once the bike is running. I have diagrams and pictures I drew of the rewires and what needs to be done.