I've been very busy lately unraveling the sins of an old fella from QLD who "restored" my machine.
After re-doing the top end (missing valve spring seats worn out valves etc.) and having his "rebuilt" magneto rebuilt I went for a nice 2500 mile ride and have been off the road ever since! Tab washers for the clutch nut are clearly hard to come by up north.
After the clutch fell off at 75MPH on the freeway the fibre drive gear on the magneto lost all its teeth and spread throughout the engine, when stripped down for a clean I discovered the con-rod bolts used are varying sized caphead screws some with washers some without and all of them a loose fit but fortunately torqued within an inch of their lives (con-rods ground to suit the varying length bolts). With the level of quality workmanship displayed on my machine I expected to find the sludge trap to be in a very poor state... but it wasn't
Since I bought the bike 4-5yrs ago I have changed the oil every 250 to 500mile using 20w50 oil for vintage engines from the supermarket, I assume these frequent oil changes are the reason she is so clean inside.