StoneRoad2013's photos with the keyword: flat-tank

Flat-tank Triumph. Probably a Model T "The Trusty" or possibly a Model H Belt drive. 560cc, 4hp regno U 3597 - first registered Jan 1921. I think this is the oldest m/bike on the run.

That's a 170cc "scooter" on the left, which contrasts with the size of the two flat-tankers to the right. A 1913 example of a Kynock with the JAP side-valve engine developing 4hp, and further to the right, a 1913 Lea Francis V-twin developing 3 1/2 hp.