Speedometer bouncing and sometimes reading fast

[Neoday2]

So my speedometer has had a bounce for the last 10k miles or so (bike has about 65k miles according to the speedo).  Sometimes I would just figure I am going between the needle's high and low point. Then the needle would settle and show my actual speed.  Not the end of the world when it was bouncing.  But now, sometimes it will read fast so I will actually be going slower than what the speedo is telling me.  I noticed this on a ride last week- it was going to be above freezing on the way home from work... and it had been a few weeks without riding.  So here I am, riding along... and then I got passed!  I felt like I was going slower than what the speedo was telling me but the needle wasn't really bouncing (I was at a steady speed, not accelerating).  So, on the return trip, I set up my phone to show my speed from the GPS.  Sure enough, at times, my speedo was up to 10 mph fast, other times it was spot on.  

It was a nice ride home into the sunset...

So my question is this- Where do I start diagnosing the speedometer?  I have seen the speedometer dampening fluid posts and was thinking of starting there, just not sure if that would fix the fast reading.

Thoughts and experience are welcome  

I'll be at the Midwest rally for sure, you just might not want me in the front of a ride until I get this resolved...

[aviationfred]

Here is an option that will give you spot on speed all the time. GPS speedometer that looks almost like the OEM speedometer.

http://www.fjowners.com/index.php?topic=12192.0


Fred

[FJmonkey]

Your speedo will eventually develop the death howl, kind of like a scalded cat. Mine did the bounce and dance till it progressed. The first time it did it I thought my front wheel had a sudden catastrophic bearing failure. You can send it out for repair or follow Fred's path of Moditus...

http://www.fjowners.com/index.php?topic=7907.0

[ribbert]

Here is an option that will give you spot on speed all the time. GPS speedometer that looks almost like the OEM speedometer.

http://www.fjowners.com/index.php?topic=12192.0


Fred

Yep, investing money in your speedo once it's gone south is a bad investment. The speedo Fred has is a cracker. A cheaper option is a GPS digital dash top unit, or as I have, a GPS/HUD unit that projects my speed onto the fairing screen just below the top lip.

IMO

Noel

[Sparky84]

Your speedo will eventually develop the death howl, kind of like a scalded cat. Mine did the bounce and dance till it progressed. The first time it did it I thought my front wheel had a sudden catastrophic bearing failure. You can send it out for repair or follow Fred's path of Moditus...

http://www.fjowners.com/index.php?topic=7907.0

Before joining this forum I thought my FJ was unique
Howling Speedo , 2nd gear which I thought was my fault , it didn't happen all the time so I just thought it was me,
6th gear which isn't there but you are always changing into it but it makes no difference to rpm
Speedo was rectified by disconnecting cable from rear, revs still work and I knew what speed I was doing, close enough anyway.
2nd gear well just wait until you're in 2nd then give it too it, 2nd to 3rd no problems and neither do the other changes