Speedometer Drive Failure?

[Maticuno]

At first I thought my failed speedometer was the speedometer itself.  When I pulled the cable off of the drive and spun it with my drill, the speedometer worked.  My next thought was the cable shrunk over time so I replaced that.  Again, when spun by the drill at the drive end everything works but not when hooked up to the drive.  I just purchased a NOS speedometer drive as the only other possible culprit, but what I'm curious about is what would cause the original drive to fail?  The "ears" on the hub and the "notches" on the drive appear to be in good shape and it also appears well greased.  Specs: 1984 FJ1100, 16k miles.

[Arnie]

About the only thing you haven't checked is the gears in the speedo drive that change the direction of movement by 90 degrees.  I'm surprised that you'd have a problem with milage that low.  Are you sure the ears were correctly located in the wheel?

[Maticuno]

Yes.  Checked and double checked and verified every time I took it apart the ears and notches were still aligned.  With the old cable in the drive and spinning the front wheel by hand every once in a while the cable will spring to life then abruptly quit.

[red]

Yes.  Checked and double checked and verified every time I took it apart the ears and notches were still aligned.  With the old cable in the drive and spinning the front wheel by hand every once in a while the cable will spring to life then abruptly quit.

Maticuno,

Sounds like the cable is binding inside the housing, but if that was the problem, the speedometer needle would jump a lot.  Since you now have all possible parts, I'd say just put it together, and go riding.
      
Check out a recent thread here, on a drop-in GPS unit:
http://www.fjowners.com/index.php?topic=12192.0

Cheers,
Red

[Maticuno]

Yes.  Checked and double checked and verified every time I took it apart the ears and notches were still aligned.  With the old cable in the drive and spinning the front wheel by hand every once in a while the cable will spring to life then abruptly quit.

Maticuno,

Sounds like the cable is binding inside the housing, but if that was the problem, the speedometer needle would jump a lot.  Since you now have all possible parts, I'd say just put it together, and go riding.
      
Check out a recent thread here, on a drop-in GPS unit:
http://www.fjowners.com/index.php?topic=12192.0

Cheers,
Red

Excellent link to that Speed Hut gauge install!  If the NOS drive unit doesn't do the trick I may have to drop some coin on one of those.  Since I'm using this bike primarily as my daily commuter, accurate speed and mileage are very important to me.  I may be the only person on this forum who actually intends to hypermile an 1100 sport touring bike  !

[aviationfred]

Here is another option, less expensive, but a small bit of modification.

http://www.fjowners.com/index.php?topic=12391.0

Fred

[Maticuno]

NOS drive unit arrived.  Before I install it, should I grease it or just leave it?  There still seems to be plenty of assembly/shipping/storage lube in the package, but the drive on the bike is packed full of grease.

[Maticuno]

The speedometer drive is installed and...it turns out it was the "ears" (someone please tell me what the appropriate nomenclature is for those) on the axle hub.  They were worn down so cleanly they looked like they were still in good shape.  Using my MIG welder, I delicately built up the tips of the ears until they were tall/large enough to engage with the grooves on the speedometer drive.  Everything works!  It's nice to have a general idea of the speed I'm cruising, even though I'm pretty sure it's reading 5mph slow  .  I think I'm going to save up and get one of the Speed Hut GPS units for increased accuracy and reliability.

[Firehawk068]

One time, after changing to a new front tire, I assembled everything and my speedometer failed to work.........................
When I disassembled it to see what may have happened, I found that the washer with the "Ears" you mentioned had become bent, and were not engaging in the speedo drive.
I merely bent them with a pair of pliers to engage the speedo drive, and reassembled everything. Worked fine as normal................

All the FJ speedos are off..............they read faster than you are actually travelling. Mine is off by about 15%