Kenny, having pulled my own shaft drive system apart 3 times for spline lubrication, as well as seeing quite a few more of friends bikes apart for the same reason, I would agree, that yes, there could be a problem with those bearings and their cups.
One friend has had his pivot bearings replaced twice in 180,000 Klm's and there is a notchiness in nearly all of the higher travelled bikes, sometimes there is a notchiness and cupping in much lower travelled bikes, such as yours.
I think that there could be a design constraint on the size of bearing used because of the location and size of wall thickness of the actual alloy swinging arm shaft housing, that is a pure guess.
Another possibility is that the bearing has a use by date that is acceptable, by the engineering standards employed today. I think back to when BMW manufactured their mid fifties to late sixties bikes. These bikes were a no compromise, no price limit, build situation. They didn't sell that well, in fact in their last year of manufacture (1969) they manufactured about 300 more units than they sold.
Since the 1969 /5 series of bikes were released BMW has been shifting ever more to a realistic compromise of affordable but reasonably well engineered machines. In todays terms, the bikes are very well engineered, and, more importantly, affordable, even though I do concede that they are at the higher end of the market.
This comes at a cost which is usually understood by the customer, to be quality cutting. All people expect to replace tyres, batteries, spark plugs and like things. However to some people it can come as a shock to realise that the life of a clutch, fuel injector, seat, etcetera also have finite lives and that the design team would have factored this into the equation.
In other words, your swing arm pivot bearings, and mine as well, probably have a life expectancy wel short of the bike as a whole. Which means that I'll more than likely be replacing these bearings, about 2 times in the life of the bike.
I consider the life of the bikes to be about 300,000 kilometres. I have had 5 BMW bikes where I have done 300,000 Klm's or more. This doesn't mean that the bikes die at that point, it means for me that the machine is starting to get rather tired and main components are starting to fall apart from extreme wear.
My last bike (R100CS) did 305,000 Klm's and then I bought my current machine (1100GS) things were starting to get to a point where I was just fixing this, replacing that, and so on. The new owner of my old machine in the next 100,000 Klm's replaced or repaired, quite a few major items that I hadn't touched during the life of the bike.
Probably not quite the answer you or I envisaged, to the question.
Mick.
