Bouncing Speedometer

[AgPilot]

89 FJ1200 speedo is bouncing around 7mph above and below what it should actually read. I just put a new speedo cable (inner and outer) on it.  Starts doing it around 40ish mph and gets worse as you go up.  If it is bouncing and I pull the clutch in and just coast it smooths right out and stays right on the mph it should be on.  What should my next step be?  Do I dare try the gear at the wheel or do I need to replace/fix the instrument cluster? It isn't making any noise I don't think, but I did just recently purchase the bike so knowing what noises should be there and shouldn't isn't my strong suit yet. In some of the threads I have read on this issue there was mention of a place I could send the cluster to get it repaired. If this is the route I need to take what is the name of that repair shop? I couldn't find the name only mention of it.
Thank you for any help,
Benjamin

[a.graham52]

I have the same issue so I'm going to watch this. But make sure the new cable has plenty of grease and that there is no sharp bends in it. Mine is aggrivaTed over bumps so I'm going to grease mine first

[FJmonkey]

Your speedo is likely to bounce like a 5 year old on 2 shots of espresso. My '86 did this, then it did it again with an '84 speedo installed. My '89 does it. Fred (Avationfred) found a digital solution that fits in the dash. I just use my GPS...

[AgPilot]

So there really isn't a fix? It really is annoying!! Why would it go smooth when I pull the clutch in?

[FJmonkey]

So there really isn't a fix? It really is annoying!! Why would it go smooth when I pull the clutch in?

Ok, you got me, there is a shop in San Diego, CA that will rebuild them. Simi_Ed had his rebuilt and was pleased with the work. Your clutch has nothing to do with the speedo function other than speed control. Without going into the depth of permanent magnets, the spin of the cable and a coil spring the bushings/bearings wear out. Simple as that. Certain speeds will cause harmonics and the speedo will bounce. The cable and cable shroud can also affect this but if properly lubed and not damaged then the speedo will eventually sound like a scalded cat (AKA "death howl" of the speedo).

[Pat Conlon]

The 3 components of your speedometer system are 1) the gear drive at the rim 2) the cable and 3) the speedo unit itself.
1) The gear drive is pretty much indestructable if kept properly greased. That said, I have read a post recently about a failure on the gear drive.
2) The cable is the same, if kept properly lubricated.
3) The speedo unit. The lubrication in the speedo unit dies out after a number of years causing wear and slop on the plastic gear bushing first, then once the shaft is out of alignment the gears themselves. The symptoms are: first the needle bounce, then the whine, then the howl, then total failure. You can try adding lubricant but in my experience you are just forestalling the inevitable. Once the bushing is worn, it needs replacement. Once the gears howl, they need replacement.

I just had my '84 speedo rebuilt ($125) by these guys: http://www.foreignspeedoinc.com/

Foreign Speedo Inc.
2246 1/2 University Ave.
San Diego, Ca. 92104
619-298-5278

Good guys. Send the entire cluster in to them. They tell me they charge extra if the speedo unit is opened and tampered with...I'm sure they were kidding. ?

FYI, This info is saved in the General Maintenence Files: http://www.fjowners.com/index.php?topic=5718.0

With the cluster out, it's a good time to replace your lamps or convert over to LEDs.

Hope this helps.  Pat

[AgPilot]

Is the rebuild a fix fix or just kind of a doesn't jump as much fix? I totally agree that the clutch has nothing to do with the operation of the speedo, but I can make it stop and start bouncing by working my clutch every time.  That's the part that seems just odd to me.

[AgPilot]

And thank you guys for the knowledge, really do appreciate it!!!!

[FJmonkey]

Is the rebuild a fix fix or just kind of a doesn't jump as much fix? I totally agree that the clutch has nothing to do with the operation of the speedo, but I can make it stop and start bouncing by working my clutch every time.  That's the part that seems just odd to me.

Any change that affects the harmonics can cause this. It is odd till you understand harmonics. Why do two similar buildings (Size, shape etc...) have two different outcomes in an earthquake? Find the natural frequency of an object/assembly and you can destroy it. Shatter a wine glass just from sound....

[AgPilot]

Thank you Monkey and Conlon, I will look into that shop.

[red]

AgPilot,

The clutch aspect is puzzling, no doubt!  Sharp bends in the cable or some lack of lubrication inside are the usual causes.  From the speedo to the spokes, the cable should be as straight as possible, and all bends in the cable should be close to the wheel hub.  Try tying the cable to the framework, to keep it very straight near the speedo end.  If that does the job, install some Ty-Wraps instead of string as a more permanent fix.  I can't imagine the instrument causing this, so I'd like to hear what the right fix will be, when you get it.

Happy hunting,
Red

[AgPilot]

It is as straight as possible and greased.  I will try securing it better and see if there is a difference.

[balky1]

Interesting. I have similar prob on my '85. It doesn't bounce constantly, but if I ride it continuously for an hour-hour and a half then starts bouncing whenever I get over some bumps. So I figured out it has something to do with forks stretching and compressing as it straightens or bends the cable that way. I lubed the gear and cable with no change and just left it like that.

[ribbert]

Interesting. I have similar prob on my '85. It doesn't bounce constantly, but if I ride it continuously for an hour-hour and a half then starts bouncing whenever I get over some bumps. So I figured out it has something to do with forks stretching and compressing as it straightens or bends the cable that way. I lubed the gear and cable with no change and just left it like that.

Balky, I think you'll find it's just the bumps, not the cable bending as the forks compress. If you hold a speedo in your hand and move it down and up quickly the needle will rise and fall. If it's lost some of its damping, it will jump over bumps.

Noel

[ribbert]

It is as straight as possible and greased.  I will try securing it better and see if there is a difference.

The best routing for the cable is as it naturally falls from the speedo to the wheel, tying it to something is more likely to cause a kink.

Noel