Speedometer Gear?

I have a '82 GPz750. When it gets colder out, it starts to buzz from the speedometer instrument panel. I've tried cleaning and lubing the cable, with no improvment.

Any suggestions? Is it possible that the speedometer gear has gone bad? If so, does anyone know where I could buy a replacement speedometer gear? Thanks!

what are you lubing the cable with?

I'm using Motion Pro Cable Lube.

I had the same thing happen on my ZN ( it has the gauge cluster similar to the GPz's) just before the speedo croaked.

It turns out the "bell" that the cable driven magnet rotates inside of had some rough areas and corrosion on it, and was interfering with the magnetic field = twang! Speedo go buh-bye.

I'd suggest removing the gauge cluster, then very carefully (the needles on those gauges are surprisingly fragile, and WILL break easily :pinch:) disassembling it and removing the speedo unit to examine it for any problems.

The speedo for my ZN is no longer available from Kawi, so hopefully the speedo for your bike is still available if you find out that your's is worn or damaged.

Post edited by: RetroRiceRocketRider, at: 2006/10/23 23:27

Actually, the speedometer is one that I purchased from you a couple of years ago (off eBay) because my previous speedometer was doing the same thing! It (the replacement speedometer) buzzed last year when it got colder and did the same again this fall. No problem when the air temperature is above 60F or so.

hey now no warrantys!

I'm very happy with the speedometer he sold me (really, the entire instrument panel). My other instrument panel's rubber push buttons were deteriorating and the one RetroRiceRocketRider sold me is in very good shape and overall it works great. He also told me about this site, so I am WAY ahead on the deal Obviously, he is really into Kawasakis - very cool in my book.

While it's possible that the internal mechanism of the speedometer may be having some problems, I've also read that other things can cause this buzzing sound. I think I've ruled out the cable, having replaced it once a couple of years ago and then lubed it, again, last week. It could also be the speedometer gear down by the axle transmitting vibration up the cable to the instrument panel.

I guess I could test that by disconnecting the speedometer cable from the speedometer gear, connecting to a drill and on low speed turning the cable. If I still hear the sound, that would rule out the speedometer gear.

It could also be the speedometer itself, as RetroRiceRocketRider suggested, in which case I'll work on fixing my old speedometer and move it over to the "new" instrument panel.

If it is the speedometer gear, does anyone know a source for speedometer gears? Was the speedometer gear in the '82 GPz750 used in any other bike?

Thanks again for your help!

Glad to see you found our little piece of KZ nirvana on the net redrkt.
And if I haven't already done so, welcome to KZr!

I just recently scored a "new to me" gauge cluster from eBay and installed it on my ZN. And although it worked perfectly and quietly at first, it too is starting to make some funky vibrating sounds at various RPM's.

I know it's not the cable since it's brand new, and I've already examined the speedo drive gear and relubed it, as well as replaced the speedo drive gear receiver with a NOS one via eBay. So it all comes back to the speedo itself as being the culprit. Besides, that's where the sound is eminating from.

Before I installed it, I thoroughly examined it and it appeared in great shape. And just like you, I've started noticing the noise happening when it's cold out (below 50*) on my morning commute.

It needs to be calibrated anyway since it's overly optimistic (it reads 100 mph when I'm actually doing about 85 mph :ohmy: ), so I plan on taking it to a shop near me that specializes in gauge restorations, calibrations and repairs. I'll also have them check to see if they can locate the cause of the noise and repair it while they're at it.
Money is kind of tight right now, so I'll post what I find out once I get it done.


ANYWAY, if you find that the speedo drive assy (ref# 41078 in the pic below) or the receiver (ref# 41064) are faulty or damaged on your bike, they just happen to fit quite a few diff model Kawis....and even current models!

Speedo drive gear assy. part# 41078-1024

Speedo drive receiver part # 41064-1006

Both parts fit way to many models and years to list them all here. I can send you the list of all the models/years that they fit either in a private message or by email, just let me know if you want it.
It will make finding them on eBay or elsewhere a whole lot easier that way.

I suppose the GPZ setup is similar to the older 650s and 1000s. If so normally putting a little lube on the speedometer where the cable goes in will fix this. Put a couple drops to lube the part that spins and a drop or two on the square point where the cable goes in.

RetroRiceRocketRider - thanks for the welcome! Love the site and have had the chance to help out (I hope!) on a couple of posts.

Could you please send the list of bikes that fit those two parts - private e-mail is fine (great diagram by the way!). I've lubed the speedometer gear; it's probably not that, but in case it is, it would be good to know which bikes to search for on eBay for them. I guess it's at below 50 degrees where I start to hear the buzzing. What material in the speedometer would be affected by cold? Rubber? Possibly shrinking?

Makes sense that there are folks that work on these gauges - looking forward to hearing how it works for you.

Darn...I tried that, but it didn't help. Thanks for the suggestion anyhow...please keep them coming!