Old Bike Australasia: Birth of the breed - The Yamaha TD-1A
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Old Bike Australasia: Birth of the breed - The Yamaha TD-1A

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By OldBike - 15 June 2015
The Yamaha TD-1A

As the 60s hove into view, the 250cc racing class was in a world-wide state of flux. The works machines from the Italian MV, Benelli and Mondial factories, plus the German NSU had gathered the world championship titles in the ‘50s, but few of the works machines ever found their way into private hands. Hence the 250 or Lightweight class, on a national basis, was still populated by ageing British specials – almost exclusively four strokes.

But companies like Adler, MZ and years earlier, DKW, had shown that the two stroke design had legs – if only the traditional bugbears could be conquered. Metal technology, lubricants, and critically, ignition systems were the ‘strokers bete noir. All three improved dramatically in the next twenty years, but it was not until the arrival of reliable transistorised ignition in the late sixties that two stroke reliability increased to the point that other technology advances could be exploited.

Of the emerging Japanese factories, Suzuki and Yamaha were making huge strides with their road-going models, but while Suzuki chased the tiny end with 50s and 125s, Yamaha concentrated on developing their YDS1 250 twin. This engine had strong links to the German Adler, including several of its inherent faults. The yawning American market was discovering 250s in a big way, to the point that the Yamaha factory sent Fumio Ito to California in 1958 to contest the grandly-titled Catalina Grand Prix with a YD-1.

The Yamaha TD-1A

Encouraged by the reaction to Ito’s sixth place, Yamaha produced the YDS1 in 1959, and soon after began offering racing kits for sale. The road-race kit  effectively replaced the entire top half of the engine, as well as the ignition system, with bigger carburettors and expansion chamber exhausts. The tuned YDS1 poked out around 25 horsepower at 9,000 rpm, but reliability wasn’t a key point. The iron-lined barrels and aluminium pistons had an unhappy relationship, with seizures commonplace.

TD-1A incorporated, for the first time, a frame expressly made for competition

Yamaha’s next step was the YDS2, introduced in 1962. Again, a race kit was offered but on the track, the Yamaha’s roadster heritage was still a disadvantage when matched against the current tackle which included two-stroke singles from Bultaco and others. A dedicated racer was needed, and in late 1962, the first of the TD1 series was displayed at the Tokyo Motorcycle Show. It was soon superseded by the TD-1A, which was identical except for longer expansion chamber exhausts. Although still based on the YDS2 lineage, the TD-1A incorporated, for the first time, a frame expressly made for competition. The forks and brakes were also specially-made items, but despite the attention to detail, the handling was significantly behind European standards.

The forks and brakes were also specially-made items, but despite the attention to detail, the handling was significantly behind European standards.

The engine too had come under intense scrutiny by the factory boffins, but in one respect was doomed to ignominy. The YDS2 (nee Adler) design had the clutch mounted on the crankshaft, running at engine speed. The shaft itself was of only 20mm diameter, and a missed gear or even an overly-energetic getaway could snap the shaft, sending the clutch flying through the outer casing. This design not only led to repeated crankshaft failure, but severely restricted the choice of gear ratios. On the TD-1A, internal ratios were the same as the YDS2 road bike, with the exception of fourth gear – meaning that first gear was unusable for anything but starts. The crankshaft-mounted clutch was probably the most significant in a considerable list of flaws that dogged Yamaha 250 racers right up until the introduction of the ground-breaking TD-1C in 1967, when the clutch was finally moved to the gearbox countershaft where it belonged. On the YDS3-based TD-1B, released in 1965, the crank diameter was increased to 25mm, which went some way to improving reliability.

The TD-1A, the new racer wasn’t a bad looker, with a fairly raunchy (for the era) shade of blood-orange on the tank, a silver-grey frame and white fairing

Harking back to the TD-1A, the new racer wasn’t a bad looker, with a fairly raunchy (for the era) shade of blood-orange on the tank, a silver-grey frame and white fairing. Of the estimated production run of 60, three are extant in USA, and three are known to exist in Australia. All these were imported by Victorian Yamaha distributors Milledge Brothers in November 1963. Two were retained for their supported riders Allan Osborne and Ken Rumble, while the other was sold to Tasmanian star Ike Chenhall. The price was £495 ($990); slightly more than the final examples of the Manx Norton of the same year.

Ike’s Bike

 

Stanley (Ike) Chenhall at the once-a-year public roads event at Longford, where the long straights suited the Yamaha well.

Stanley (Ike) Chenhall, born and bred in Launceston. Via the usual fare of Nortons, Velocettes and other British tackle, he established himself as one of the leading lights on the local racing scene, and certainly one of the most popular. The arrival of the new Yamaha was the cause of much celebration in Chenhall’s home town of Launceston, to the point that the local newspaper, the Examiner, sent a photographer to the Chenhall home to record the machine’s public debut. Before its despatch from Melbourne, Milledge Bros had thoughtfully adorned the white fairing with Ike’s famous racing number 14.

Aboard his new and expensive pride and joy, Ike was immediately competitive at the local circuits Symmons Plains and Baskerville, and especially so at the once-a-year public roads event at Longford, where the long straights suited the Yamaha well. For the next six years, Ike and the TD-1A were rarely outside top first three.  Then, in 1970, 43-year-old Ike lost his life while plying his trade as a timber cutter.  A year or so previously, Ike had sold the Yamaha, now substantially outdated and uncompetitive, to the Tasmanian Yamaha distributors, whereupon it passed through various hands before vanishing from the scene.

For most, the Chenhall Yamaha was but a distant memory by the time it appeared as a lot at Tulloch’s Auctions in Launceston in 2002. There were few bidders for the tatty looking old racer, but John Rettig, a Hobart-based former successful rider, knew what he was looking for – and a bid $2,000 secured it. John had done his homework and had identified chassis number T1-077 as the famous Chenhall bike. The frame still carried the extra lugs above the footrests where Ike had fitted a cross-over shaft to swap the gear change from left to right. Ike’s widow Jean sat silently in the back of the auction room, and was delighted when Rettig secured the machine. Jean subsequently gave John an enormous collection of material amassed over the years, including Ike’s famous blue pudding basin helmet.

Thus began an 18-month rebuild that involved Rettig in a global search for the missing parts to restore the TD-1A to its former glory. There were dozens of small bits and pieces to be sourced or made, but in November 2003, exactly 40 years after the Yamaha arrived in Tasmania, it rolled out of the Rettig workshop and was fired up. It made its public reappearance as part of Tasmania’s inaugural Australian Motorcycle Week, when Rettig, wearing Ike’s helmet and goggles, gave it a nostalgic blast up Longford’s main street and round the Country Club Hotel – the most famous and enduring landmark from the glory days of the annual Longford road races. John’s stunning restoration was the subject of enormous attention from the appreciative crowd, which contained a very proud Mrs Jean Chenhall.

John Rettig admits that a modern ignition system (replacing the magneto) would probably transform the engine’s characteristics, as well as making it significantly easier to start. But extra performance is not the intention here. The venerable Yamaha will only henceforth be called upon for demonstration runs, and it is the way it was, after all.

The Rettig TD-1A is a fascinating reminder of the bike that started the 250 class revolution more than 40 years ago. Yamaha, to its credit, learned quickly from its mistakes and every subsequent model was an improvement on the previous. Within ten years of the TD1’s introduction, grids worldwide were totally dominated by the Yamaha twins in their various forms. With the British tackle gone and Italian racing lightweights scarce, you can only wonder if road racing would have survived at all without the lineage that the TD-1A started.

Protect your Yamaha. Call Shannons Insurance on 13 46 46 to get a quote today.