Here are a few more things that you might not Know
1922 DOHC 350cc JAP
This was probably the first DOHC motorcycle engine. Designed for the 1922 TT. There was also a 350cc version which won the Brooklands 200 mile race in 1922 & 23.
1931 Rudge 250cc Radial 4 Valve
This had 4 valves radialy disposed in a hemi head. This gave Rudge a runaway 1-2-3 win in the 1931 Junior TT and a 1-2-4 in the lightweight race. Although noisy and demanding to keep in tune this engine had few equals for many years.
1948 Wooler 500cc four
This engine designed by John Wooler was unusual in that pairs of cylinders were arranged atop each other and the crankshaft was connected to the conrods by a rocking beam. This gave a narrow engine but it had a high center of gravity.