Speedo Issue

[paratrooper34]

Hello All,

    So I replaced the speedometer on my '88 K75S with one that shows the rate of speed, but the odometer and trip meter do not work at all.

    A little background:  When I bought the bike (about three weeks ago), the speedo only worked intermittently.  So I found a used instrument cluster and installed it.  When I took it for a test ride, only the speedo worked, not the odometer and trip meter.  The trip meter does reset correctly, but stays on zero during test ride.  Figuring I can do without the trip meter and odometer at this point, I swapped out the speedo into my instrument cluster (my instrument cluster is in better shape than the one I bought).  Same result when on a test ride.  Everything else works as it should including all lights and tachometer.

    When I got into the internals of both clusters, nothing seemed to be messed up and all of the gears I could see looked good.  Does anyone have any ideas on how I can get the odometer and trip meter working?  Is there anything to look for inside the cluster?  If I have to send it out for repair, I am willing to do that.  Are there any suggestions on who to send it to?

Thanks in advance!

[Laitch]

Here is where you'll find a lot of information about instrument cluster diagnosis and repair. This outfit seems well regarded when it comes to instrument cluster repair. He promptly answered my query, I can tell you that much.

[paratrooper34]

Here is where you'll find a lot of information about instrument cluster diagnosis and repair. This outfit seems well regarded when it comes to instrument cluster repair. He promptly answered my query, I can tell you that much.

Lots of good info, thanks.  Only thing I could readily find on there was reference to the three-prong connection behind the speedo.  So I took it off and got inside to check that.  All the connections look very clean with no corrosion.  So I reinstalled and took it out for a test ride...and nothing still.  Dang.

[rbm]

Tell me if I understand correctly:
- you had a cluster with an intermittent speedo
- to solve the problem, you purchased a used cluster and replaced your existing cluster with the new one
- the new cluster has a speedo that works but odometer and trip did not work
- you swapped back your old cluster, but not before extracting the speedo unit from the new cluster and substituting it for the intermittent speedo you originally had
- same symptoms appear with the odometer and trip after the swap

If this interpretation is correct, then the behaviour you see is totally expected.  The stepper motor for the odometer / trip meter is driven by the same signal that drives the stepper for the speedometer (there is one signal that drives two different motors)/  So, you have to examine the gears inside the odometer to ascertain their condition.  Most likely you were sold a defective cluster and the gears in the new one are broken, hence the non-working milage indicators on your new cluster.   Seek the services of a competent shop to repair the gears or find out why the original speedometer is intermittent.

[stokester]

Sounds like the gears are TU.

Not too long ago I noticed while documenting some maintenance that the odometer mileage had not changed and a test ride confirmed that neither that nor the trip meter had changed.  Some searching here led me to disassemble the cluster to find a common problem where I found the gears stripped.

I found that odometergears.com made the replacement gears and included instructions for a BMW motorcycle.   As a big plus, he's just down the road from me in Newport News VA so I coordinated with him and stopped by his house and we repaired the cluster.

All is good.

[paratrooper34]

Tell me if I understand correctly:
- you had a cluster with an intermittent speedo
- to solve the problem, you purchased a used cluster and replaced your existing cluster with the new one
- the new cluster has a speedo that works but odometer and trip did not work
- you swapped back your old cluster, but not before extracting the speedo unit from the new cluster and substituting it for the intermittent speedo you originally had
- same symptoms appear with the odometer and trip after the swap

If this interpretation is correct, then the behaviour you see is totally expected.  The stepper motor for the odometer / trip meter is driven by the same signal that drives the stepper for the speedometer (there is one signal that drives two different motors)/  So, you have to examine the gears inside the odometer to ascertain their condition.  Most likely you were sold a defective cluster and the gears in the new one are broken, hence the non-working milage indicators on your new cluster.   Seek the services of a competent shop to repair the gears or find out why the original speedometer is intermittent.

Almost all correct except the symptoms are not exactly the same.  Original cluster had speedo/odometer/trip meter that only works intermittently.  Used replacement cluster has working speedo but odometer and trip meter do not work.  I switched them because I would rather have a speedo that works (albeit w/o odometer and trip meter) as opposed to one that doesn't work.  All visible gears in both units look ok to me.  Can the assembly be further broken down to expose all gears to locate a problematic one?

[paratrooper34]

Sounds like the gears are TU.

Not too long ago I noticed while documenting some maintenance that the odometer mileage had not changed and a test ride confirmed that neither that nor the trip meter had changed.  Some searching here led me to disassemble the cluster to find a common problem where I found the gears stripped.

I found that odometergears.com made the replacement gears and included instructions for a BMW motorcycle.   As a big plus, he's just down the road from me in Newport News VA so I coordinated with him and stopped by his house and we repaired the cluster.

All is good.

I actually have a non-working cluster that came as a two-fer when I got the replacement.  Maybe I will experiment with that one to see if can get in there to examine the gears.  Thanks.

[stokester]

I actually have a non-working cluster that came as a two-fer when I got the replacement.  Maybe I will experiment with that one to see if can get in there to examine the gears.  Thanks.

Take a look at Jeff's repair instructions: http://www.odometergears.com/documentation/BMW_Motorcycle_MotoMeter_Odometer_Gear_Replacement-.pdf

[paratrooper34]

Take a look at Jeff's repair instructions: http://www.odometergears.com/documentation/BMW_Motorcycle_MotoMeter_Odometer_Gear_Replacement-.pdf

Ooh, that is going to be helpful, thanks!