On an overcast Sunday afternoon at Brooklands, Major Frank Halford breaks the 500cc World Hour Record at 76.74 mph aboard a "Riccy", along with the 50-mile standing start record with a speed of 77.27 mph and the one-mile British record at 87.8 mph.
Similar to the earlier SD model, Triumph's Model 'R', their first four-valve, 500cc, OHV motor was introduced in 1921.
The 21 bhp, four-valve head (with twin valves set at 90 degrees apart) was designed by Sir Harry Ricardo and Major Frank Halford with the idea of producing an engine which could maintain maximum power at sustained high speeds using a machined steel cylinder and an aluminum piston. The motor was nicknamed "Riccy" by it's two designers.
Sir Harry Ricardo was an engineer who developed the modern understanding of engine breathing and combustion processes.
In keeping up with the Jones', BSA produces its first motorcycle, a side-valve 770cc V-twin using vertical valves, aluminum slipper-type pistons, one-into-two exhaust manifold, two independent oiling mechanisms. The "secret project" cost over 10,000 pounds and took 18 months. Initial tests at Brooklands had promised speed, but at the TT, it was sidelined by the end of the second lap as the result of melted pistons. Should have kept it a secret.
Today in motorcycle history proudly supports the National Association for Bikers with a Disability (NABD). www.nabd.org.uk
