CAMPLATE/QUADRANT SPINDLE BOLTS

To be honest, I wouldn't want to ride a Commando if I hadn't looked inside the box  (or someone competent had built it)...The risk of a dodgy layshaft bearing is just too great - maybe even more so with a low mileage bike...but in answer to your question, neither quadrant nor cam plate can go anywhere if you remove the screws. Replacing the 'O' rings is a fiddle but possible, while you're at it.

Dodgy layshaft bearing is highest risk in 850's, can happen at any mileage but mine went at 14k miles. Went from working perfectly to only having 4th in 3 to 4 miles, opening it up I found loose bearing balls split in half no doubt having being minced by the gears. A full lockup was a possibility. If you have no record of a previous owner fitting the upgraded roller bearing or ball with phenolic plastic cage then its time to go in and check. It won't be a full rebuild if you don't open the gearbox up.  

Is this the bearing at the far drive side end of the layshaft or inside the kick start shaft? And is it only a Commando problem? Should we be worried about earlier bikes? And is a roller the fix rather than ball  bearing? It seems strange that it is such a problem (which evidently it is).

... heat the casing to fit the bearings. As said, the housings are marginal and the less force applied the better. I think earlier (pre-"AMC") boxes had the roller bearing as standard but am not sure of this.

The layshaft bearing is an issue with the AMC box, the heavier the load the earlier it will go and also it depends on who made the bearing and where it came from. Worst offender seems to be an FAG made in Portugal and this seems to be related to the method used to join the 2 halves of the cage together. Your ES2 would not be a worry but Atlas/Commando and especially the 850 Commando are a worry. As Mick Hemmings successfully fixed his boxes with a ball bearing but with a phenolic plastic cage then the ball bearing has the capacity to cope but the standard cage does not. A roller bearing is cheaper than the Mick Hemmings special ball bearing but the roller allows the layshaft to float so shimming on the endfloat is required or you could find the box jumping out of first with a heavy load. When mine went the cage had disintegrated allowing the balls to bunch up on one side and then drop out, if the cage had stayed together then likely that ball bearing would still be there.