I thought that might get some attention. I love this forum. There are some awesome ideas and some pretty out of this world, complicated responses to simple problems.
I don't fix Beamers for a living so I don't feel guilty looking for answers here and not paying for the expertise. I think if you are a for-hire wrench and grabbing the great info available here, you should be paying a subscription, just like I do for Mitchell or Alldata.
My buddy and I went for a boo this morning with some of those noisy twin guys. Lovely day but he complained he was "up" there in the speedo to keep up. Really, we weren't crazy fast, a few sixty's but most were fifty.
We swapped bikes and I threw my GPS on it. WOW!! He was 8 MPH slower than the speedo indication. I checked the tire size, bang on, tire pressure, perfect. I took the cable out at the drive end, free. The speedo drive was turning freely....................
Couple things pop to mind, the speedo head is wildly inaccurate or it's from another oilhead with different size front tire. Here comes the questions:
Do the various oilhead models come with different front wheel diameters? Aspect ratio won't make that much difference.
Is there an adjustment or a calibration method for the speedo head? Who could do that?
I would doubt the drive could read too fast, slow I could see if it had a tooth or three missing. is it possible to have different speedo drives for different models?