The separation of the two halves of the crankcase is quite straight-forward and will be accomplished easily after taking out all securing studs and bolts,
The Mainbearings - a roller race on the near side and a ball race on the offside should be replaced if there is any trace of roughness or if any up and down play can be detected. The ball race and the outer rings of the roller race are readily removed without special tools if the Crankcase is heated first, and smartly brought down on to a solid wood surface to jarr them out of place, the centre ring of the roller race can be prised off the shaft.
Whilst the Crankcase is separated remove the oil-filter-plug from the offside rear. Clean out all oil passages.