1952 es2 plunger rear chain adjustment

I also have a plunger ES2. To my eye it looks as if the rear chain does not need quite as much slack as would be necessary for a swing arm model. But there is a big risk to the gearbox bearing if you get it wrong and it has tight spot. I make sure I have 1" free movement sitting on the stand, and no concerns if it is 1/2" more than that in places. Important to fully rotate the wheel and test all positions as there will be a variation.

Norm

... is at its tightest at the extremes of movement up & down unlike swinging fork layouts. You therefore need to check it on the centre stand with the rear wheel clear of the deck. Alternatively on its wheels with plenty of weight to compress the springs.

Norton motorcycles 1928-1955 Temple Press published manual has adjustment instructions for 5/8 of movement with weight of machine on wheels, spring frame models. Good luck -Pat

.. that the figure may differ between Inter and ES2 frames as the plungers on the former seem to lean forward at the top more. I would think 5/8" a little on the tight side as it will reduce significantly with the weight of a rider especially over sleeping policemen and the like.

Inter only lean forward because the engine/gearbox are lower.  So they should behave the same.

.... to make sure when the full load is on the machine the chain still has vertical movement.  I usually adjust for a loose inch before sitting.