Well as I see it most of the problem is the design.
The bolted on outrigger bearing support can't be aligned properly to the shaft and doesn't accommodate tolerance of manufacture. Basically the register of the bearing housing dictates where the centre of the shaft should be but the shaft centre isn't there as it's dictated by the shaft it bolts on.
Remove the close fit of register so bearing centres on shaft and rely on the bolt clamping to hold the bearing housing.
Normally when using vertically split cases (eg a normal gearbox) the distance between the bearings is quite long and the shafts and bearing can cope with slight mismatch between bearing centres. There will always be some mismatch as the cases (and middle plate for gearbox) are all made on different machines and not selected for matching centre distance. Norton Commando had built up cranks that bolted 2 1/2 cranks to a central flywheel, had crankflex issues and solved them with "superblend" bearings. These are neither a ball or plain roller but a barrel bearing that self aligns. but that can't cope with a shaft running off centre to the bearing housing.
Triumph Trident T150/160 and Matchless twins were a right game. T150 had 3 part crankcase and had to be set up with a dial gauge so the 3rd part fitted. Matchless had a middle bearing that was on horseshoe shaped plate. That bearing was assembled and the crank with plate bolted into one case, again a dial gauge was needed to get it true so the other 1/2 case could be bolted on. Get them wrong and you wiped out the crank in a few 1000 miles. Though hopefully it was so wrong it was too tight to turn.
Don't get these issues with horizontally split cases as the cases are all line bored.
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Originally Posted by sideways14a
Annual service done, nothing required but a wash at this stage 
