1982 JAWA 500 Speedway Twin Cam
1982 JAWA 500 Speedway Twin-Cam
Rapid response
The arrival of the new British Weslake engine on the speedway scene in 1975 proved a bitter blow for the Czech Jawa factory. Their alcohol-fueled overhead-valve single had dislodged the British JAP unit from the front- rank position that it had held from 1931 until the start of the 1960s, when the Czechs had managed to gain the upper hand.
A Modern Opponent
But in 1975, Jawa found itself confronted by the thoroughly modern four-valve Weslake engine. It was lighter and more powerful and gave Peter Collins the 1976 World Championship title in Poland.
World Champion
Jawa was not slow to respond – the old overhead-valve single was swept aside by a new four-valve engine with twin overhead- camshafts driven by chain. At that time the works riders were a remarkable trio: New Zealander Ivan Mauger, Swede Ole Olsen and Australian Barry Briggs. Mauger took the World Championship for Jawa in 1977, and the Czech engines reigned supreme for the next five years. The original models had 88×82mm engines, but later examples used dimensions of 85×87mm. They ran at the very high rate for their day – of 8500 rpm, developing 55 hp on methanol with a compression ratio in the region of 14:1. The Jawa twin-cam remained in production for ten years before being replaced by a new engine with a single overhead-camshaft.
SPECIFICATIONS
Engine: 494cc (85×87mm) air-cooled single- cylinder four stroke; magneto ignition
Power Rating: 55 hp @ 8500 rpm
Valves: twin overhead-camshafts; 4 valves Fuel System: Amal or Dell’Orto carburetor Transmission: direct-drive (speedway version) or 2-speed (long-track version); chain final drive
Suspension: telescopic forks (front); rigid (rear)
Wheels: 2.78×23 inch (front); 4.00×19 inch (rear)
Weight: 187 lb
Maximum Speed: 80 mph (Speedway version)
Simple basic even – the 500 Jawa Speedway Twin-Cam weighed a mere 187lb, which enabled the bike to accelerate from 0 to 60 mph in less than three seconds.
This and many other Atlas Editions Classic Motorcycle cards are available for purchase.
