(08-31-2020, 06:18 AM)pekingduck_imp Wrote: I would expect any Japanese shaft/final drive to work properly, with little or no problem for at least 100k miles, and I have no qualms about them.

But 5% of BMWs, 1 in 20, is a pretty high percentage, even assuming a higher mileage accumulation. Certainly not what would be car-like reliability.

Back in my dealership days, I'd see rear sprocket teeth worn, folded over so the tips were almost touching, with red iron oxide powder caked and dusted under the countershaft sprocket cover. On street bikes, ridden in, the clueless owner usually complaining the clutch has been slipping.

On one, the front sprocket was spinning after it had hammered and eroded the splines on the countershaft itself. We arc-weld the sprocket to the shaft. My point is that chains can take a lot of abuse/neglect and the failure is not sudden or completely debilitating.