Creg Ny Waaahhh - Ago's TZ350

My Instagram video reminded me how excited some were when the Yamaha RD350LC arrived: a “TZ or the road” they said. They were wrong and the work needed to convert the roadster to TZ spec was such that it wasn’t allowed to compete in the Formula 2 world championship. So here’s Ago on the real thing in 2011 on a celebration lap at Creg Ny Baa. That the TZ was on the way was hinted at in 1971 when air cooled factory twins first appeared with four lugs welded on the front down tubes, upon which a radiator could be mounted. By the end of that year the first prototype water cooled top end was ready for the 1972 season. These were used to great effect, especially Jarno Saarinen who clinched the 250cc championship that year, and finished a close second in the 350cc class behind Agostini and the MV Agusta. By the end of 1972 the Yamaha factory was ready to start production of the water cooled production race machine, the TZ350A. Based loosely upon the R5 roadster, making it eligible for US competition, there were some notable differences. The primary gears provided the drive for the water pump, and the barrels were one piece allowing the transfer ports to be larger than with separate cylinder castings. The inclusion of water cooling and other improvements over the TZ350’s air cooled TR3 predecessors saw Yamaha's 350cc production racer become almost unbeatable in the hands of the right rider. Claimed power was 60bhp at 9,500rpm, primary drive by gear to a six speed gearbox. The chassis was utterly conventional with a tubular steel frame, 18” wheels and a four leading shoe front brake. So suddenly here was a 350 that could, and would, win the Senior TT. This upset to the status quo would have quickly resulted in a whole field of two-strokes, and rendered the British singles obsolete overnight. So the ACU insisted all Senior entries “must be over 350cc”. Of course it didn’t take long before people such as Ted Broad repurposed the TZ with eccentric crankpins made up to marginally increase the stroke and give 352cc, but it at least gave the lovely old English singles a few years grace. Text from my Classic TT Racers book, photo courtesy iomtt.com / Dave Kneen / Pacemaker

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