Sent by Reece, this is Jeff's 1929 Model 21. This motorcycle has a 490cc engine and 3-speed gearbox like the Model 18 but with a dry-sump lubrication. The reciprocating plunger oil pump was designed by Walter Moore and first used on Norton motorcycles in 1925. The external control on the lower timing case controls the pick-up level of the scavenge pump; set in the 'high' position the oil level in the crankcase rises and the engine becomes a semi-wet-sump.
