STTES[23] - military bikes

Significant contrast in military motorbikes.

on the left is a BSA M21 [600cc side-valve] from WW2 [development began in 1937]. The M20 & M21 were some of the most numerous models supplied to the British Army.
on the right is an Armstrong MT500, developed in the 1980s. Note then lighter construction and much higher ground clearance.