Italian builds replica of 1933 Rudge racer
A development of Rudge’s TT Replica motor, only around 20 Dirt Track model engines were made. This one, which once powered a racing outfit in a TT Rep frame, has been restored to its former glory
Every motorcycle club needs someone like Dante Petrucci. He’s the driving force behind the Italian section of the Rudge Enthusiasts Club and every year at the ASI Motoshow he brings together an impressive display of Rudges and Python-engined specials from companies like Miller, Linx, Ganna and Simoncelli. There’s always a star at his show – one year it was Rudge TT Replicas used by Enzo Ferrari’s race team, other years it has been a double-overhead-cam conversion and a V-twin with a home-made crankcase and Ulster top ends. But this year he brought along a Rudge that could have maintained the pushrod four-valve engine’s competitive edge. In the 1930s Les Graham (who would go on to win the first 500cc World Championship title in 1949 on an AJS Porcupine) and his friend Roy Evans both raced Rudge TT Replicas. They were always looking for ways to improve performance – and that’s where the Dirt Track engine comes into the picture. Rudge Whitworth had introduced the new engine towards the end of 1932. The crankcase mouth was beefed up, as was the cylinder barrel which featured shorter fins. Six through-bolts secured the bronze head to the crankcase, sandwiching the barrel between. The modifications allowed a higher 10:1 compression ratio without the risk of blowing the top end off the bottom. The semiradial head had two parallel inlet valves and a pair of radial exhausts, as on the 1932 TT rep.
Smaller flywheels in the engine, compared to the 500cc TT rep, helped deliver the quicker acceleration demanded by speedway (or dirt track) bikes. Instead of dry sump lubrication with a duplex plunger oil pump, the Dirt Track engine used a total-loss system last seen on the 1928 models. The 1933 Rudge catalogue offered the Dirt Track Model at £79, a whopping £14 more than a 500cc TT Replica, but it would be the last year it would be listed and only about 20 of these DT engines were made. Les Graham got hold of engine number D1, Evans picked up D5 and they mounted them in their race bikes. Evans hitched his Rudge to a sidecar and had many local wins, but was outclassed by 600cc cammy Nortons on longer circuits. Rudge D5 was sold to vintage sports car racer George Burton, who was passengered by Eric Stevens. John Clayton (later president of the Rudge Enthusiasts Club) was the next owner of D5 and its TT Rep chassis.
“After John passed away, our friend Walter Baldissin bought Rudge D5. It was dismantled and stored in a wooden box but it was all there,” says Dante, who is also the man behind Registro Storico Italiano Rudge. “I did the historical research while club members Barbadoro Paolo and Massimo Apolloni carried out the restoration. We only needed to buy new valves and springs and a few minor parts, so it was very easy to put it back together. The engine is very strong, and it runs a treat!”
Walter Baldissin owns Rudge D5, which only needed new valves and springs to run again Cylinder fins were skinnier and flywheels made smaller in the Dirt Track for more rapid acceleration 2 Bowden steering damper is cableoperated by a lever on the handlebar, so you don’t have to take your hand off the bar to alter it 3 Semi-radial cylinder head was the same as used on the 1932 TT Replica 4 Bike has been fully restored after being dismantled and stored in a box 5 Italian Rudge enthusiast Dante Petrucci on the bike powered by Dirt Track engine number D5 1