Velocette (Sid Willis)

sidwillis1953 sidwillisdesmovelomockupsmall

Regarding Sid Willis’s desmo KTT/KSS. I knew Sid well & often visited him up to his death & spoke to him at length on his bikes & exploits. He was a champion 250 rider here in Australia & had several ex works Velo engines & parts. He also went to Europe in 1953 with another Australian Tony MacAlpine. Sid took his own 250 DOHC racers, initially in a rigid frame, however after several meetings in Europe, notably Mettet where the handling on the cobble stone circuit meant he was at a disadvantage on a rigid, when he went to England, he arranged for Doug St.Julian Beasley to make him a frame. He came 5th in IOM 250TT, the first privateer home. The engine had one of the prewar works Velo DOHC cambox & cylinder heads fitted. Sometime in the 1950s, Sid made his own desmo cylinder head & cambox. He used a mk.2 KSS head that he machined all the cambox off & cast a special aluminium cambox to fit on it & used rockers that he made by silver soldering parts off a spanner to, to actuate the valves. The bike certainly revved & Sid said it would do 10000rpm, started easily, it had no compression,. But as you quickly turned the motor over, gas pressure sealed the valves. He tried it at a local racing circuit, Mt. Druitt & all Sid was interested in was lap times…if it wasn’t faster around the circuit than his ex works DOHC, then it was of no interest to him This proved to be the case & he broke these fabricated rockers several times. The bike languished in his shed for a year, unused, then Sid re tried it, with the same results. As a failure, Sid broke the engine up, melting down the aluminium cam box for another project. So it no longer exists. I have never seen a photo of it. However Sid made up a mock up of the valve mechanism on a steel plate to determine how he would make the desmo work. To my delight, Sid still had this, rusty, in is scrap metal tin. “could I have it…?”…yes & I still have it today. There was another desmo here in Sydney in Late 1950s & I have a good photo of the bike without it’s petrol tank. The name Hinton is famous in Australian racing circles & well known in Europe also. The father, Harry Hinton, senior rode for Nortons in late 1940s & then his two sons, Eric & Harry, junior went to Europe on numerous occasions. Harry junior was killed in Europe. They had much ex works Norton stuff & made their own desmo Manx.
Text by: Dennis Quinlin from Sydney, Australia (February 2007).
Article titled: “Sid Willis’ 1936 250 Velocette : From backyard to the isle of Man”.
More research to be done. Better/more pics and more facts are to be expected soon.
[Classification = Group 8 A]