These are the Braid brothers during the 1914 TT on the Isle of Man. The model numbering system has been in use since 1915, so while these motorcycles look like TT Model 9's they could be 3 1/2 HP models. Large boxes are fitted to the saddle tubes; are these oiltanks or toolboxes? The old Norton logo is still used.
Roger:"The Nortons have a two speed epicyclic gearbox on the end of the crankshaft. The lever changes between the two ratios without a clutch."
Bigport:" I think the machines are fitted with Brampton variable gears. The construction widens or closes the pulley flanges, thereby varying the gear ratio. See the description above.