‘The best years of my career’
What was life like, in the sometimes 24-hour Banbury sweat shop where Kenny Roberts built his GP bikes? For Tom O’Kane, “they were the best years of my career.” At Kenny’s insistence, everything was bespoke. “For example, choosing a power-valve motor. You could go to your local Yamaha racing spares shop and buy the ones for the YZR250. Trouble is they would look identical to the Yamahas’, and it would look – at the very least – like we’d copied them. So I ended up designing them from scratch. We had a carbon housing, some Swiss DC motors, and everything was custom made. “The electrical generators … most of the parts for them came from a company in England making disc brakes for mountain bikes. I went to them because none of the engineering companies in the Midlands had time for small, fiddly items. They were all too busy doing F1 stuff or bigger projects. So our generator rotor was put together using bicycle crank tools, funnily enough – the spanners for bicycles. “At that time we were having debates on which way to spin the crankshaft, so we had primary chains and sprockets made [in addition to the established gear primary drive]. In one practice session, with Mike Hale riding, we did one run with sprockets, then clutch off, cover off, sprockets off and primary gears on, and on the other side the trigger wheel for the ignition. Then the bike went out with the crank running in the opposite direction. We did that in one practice session. Really good information… same bike, same rider, same tyres, same session. “The other factories were also experimenting like that, but I doubt very much ever on the same bike in the same session.”