Charles Sgonina (b.1901) built an advanced DOHC racer in 1922. The cylinder head was of his own manufacture mounted on a Norton bottom end with bevel-driven cams. The engine was housed in a frame from Sunbeam using forks of the same brand. Transmission was by chain and it had a dummy-rim rear brake.
Sgononi's first attempt at a racing special was based on a sidevalve BRS Norton which he converted to OHV in 1919, some years before Norton introduced their own OHV motorcycle. Subsequently he developed a number of different configurations including chain-driven OHC before settling on a bevel drive system. During this period a supercharger was added with spectacular, if somewhat inflammatory, results.
1923 saw the final phase - a DOHC head with 90 degree inclined valves. Norton thought this a rather good idea and 14 years later built their own.
Born into a motor engineering company in Wales, he became a works rider for Triumph and tested the four-valve Ricardo Triumph at Brooklands. He raced in the 1921 Isle of Man Senior TT and then in the French Grand Prix, coming in third behind the Sunbeams of Alec Bennett and Tommy De la Hay.
C. Sgonina was listed to ride a Triumph Ricardo in the 1922 Senior at the IOM TT.
The Sgonina machine was displayed in Murray's Museum on the Isle of Man in the 1970s, and then disappeared for some time after the death of John Griffith, the owner, in 1983.
Called the Sgonina-Special by its enthusiastic owner, C. Sgonina the well-known Welsh speedman, this attractive looking mount is based on a Norton, but has been much altered. The new overhead camshaft is chain driven off two sprockets on the original camshafts. Frame and gear box resemble the track Sunbeam.
The Motor Cycle April 27th, 1922, page 545
Sources: thebestmotorcycle.blogspot.com, southwalessectionvmcc.co.uk
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