‘THE SENSATION OF 1966 WAS SUZUKI’S T20 SUPER SIX... IT OVERTOOK BRITISH 500s’
Villiers twins’ performance was moderate; when the 4T arrived in 1963 to supersede the 16.5bhp 2T, it was revvier but less tractable and only offered 0.5bhp more. Villiers’ hottest unit was the 32bhp 247cc (68 x 68mm) Starmaker competition single that powered Cotton and DMW road racers. Cotton used it to take class wins in mid-1960s 500mile Production races with the rule-bending Conquest. Hitting 105mph in a press test, it was a teenagers’ dream with restricted availability.
Britain’s dying industry saw 11 two-stroke makers disappear by the late 1960s, as Japanese brands advanced. Yamaha led the charge with its YDS2 250cc five-speed twin. When I spotted one as a 14 year-old at the ’63 TT, I instantly related it to the astonishing 140mph that Yamaha’s 250cc RD56 twin hit in a speed trap that week. A year later, the YDS3 with Autolube that replaced crude pre-mixing appeared. A 90mph-plus maximum made other 250cc ‘sports’ strokers look silly –but the YDS3 was expensive, fuel consumption inevitably rose with performance and switching to nonjapanese tyres was recommended.
The sensation of 1966 was Suzuki’s T20 Super Six (called the X6 Hustler in the US), a whispering 90mph-plus sixspeed twin with Posilube oil injection that showed 100mph on its 120mph speedo as it overtook British five-hundreds. Yamaha countered in 1967 with the electric-start YDS5, while Kawasaki unleashed the compact 250cc A1 Samurai twin featuring disc-valve induction and Superlube oil injection, tested at 99mph by Motorcycle Mechanics.
The scene was set for escalating 250cc wars in
the next decade...