Originally Posted by SUMmer123
Dear all - advice needed
My 2000LT has developed a speedo fault. ITs needle started acting strongly a few weeks ago (Moving / bouncing up and down while bike moving) then it stopped working altogether
this may be completely off-base, but worth a try.
I had this issue on one of my previous bikes; it was either the K100RS or K1200RS. On the one that failed, there was a tooth ring pressed onto the crown wheel in the final drive - the teeth of the ring passed under the speed sensor to drive the speedometer.
The tooth ring slipped of the crownwheel a bit and was not turning. Actually, the viscosity of the fluid was making it turn a bit - thus, speed indication was erratic, either zero or jumping, always below real speed.
I detected it by pulling the sensor out from the FD housing. The teeth of the sensing ring are visible with a strong light through the sensor hole. They may still move with the wheel being rotated - I gently stuck a thin screwdriver and tried to prevent the ring from rotating: it did stop, proving that it got detached from the crown wheel.
The diagnosis was very simple, the fix a bit more involved. I opened the final drive, cleaned the mating surfaces with solvents and used one of these ultra-strong epoxies (like J-B Weld) to reattach the tooth ring to the crown wheel - it was spun free and would not press-fit anymore.
Now, it is a few years since I had a K1200LT final drive apart. I do not remember how this is set up internally. If it has similar construction to the older RS bikes, you could have this issue.
So, if I were you, before spending more money chasing electrical gremlins, I'd pull out the speed sensor and have a quick look inside the FD. All it'd cost you is a little bit of time.
Good luck. Robert.