This is what happens when the Japanese get it so nearly right and proceed to improve on the ethos year on year, finally nailing it at the third attempt. First seen in the UK during 1962, the TD1, based heavily upon the YDS2 road machine, made competitive 250cc racing a real possibility for all. The TD series made it possible to win at all levels, and against machines of all capacities, with 30bhp on tap and weighing a mere 113kgs even the mighty 500s had to watch their backs.
Throughout the early 60s Yamaha had developed the road machine based 250cc racers into serious challengers for race glory. The early TD models were fast and furious but fragile, often seizing within sight of the flag or throwing the whole clutch assembly out of the left hand casings. They proved popular too with over 300 TD1B models sold during 1966.
For the C model the fast spinning clutch was moved from the end of the crank to its more usual position on the gearbox input shaft. This reduced its rotation speed by two thirds, and in turn made it a hardier unit, with less stress being placed through the unit, the old days of constant clutch adjustment and regular failings were now gone. On the YDS5, the road machine that provided the engine casings for the TD1C, the clutch was replaced on the end of the crank by an electric starter, obviously not needed on a racer so could be junked to save weight.
With a massive 8bhp power hike form the B model, the performance was staggering with a top speed near the 130mph mark, depending on gearing, the Yamaha twin soon made an impression upon the racetracks of the world fast becoming a real giant killer. Gary Nixon rode a factory-backed model to success at Daytona in 1967, just weeks after the types release, he went on to be dominant on his Yamaha all that year, winning Indianapolis and many more major stateside races. In the UK the type was gaining many fans, the reliability problems of early two stroke racers fast being erased from riders memories. The TD1C also saw GP action in 1968, Rodney Gould pitched his Bultaco framed Yamaha twin against the works V4s of Read and Ivy, clearly never matching the outright speed of the factory racers, but proving enough to rank him 4th in the 250 championship come the end of that season. The following year the FIM announced that 1970 would see the exotic multi banned from the 250cc class and Yamaha, seeing no point in continuing their GP program, withdrew the full factory support, leaving the all-new TD2 as the best of the oriental race machines for 1969. The TD2 saw many changes especially with the chassis; the frame now starting to look more business like while many engine parts remained the same as the TD1 series. Australian Kel Carruthers and his screaming four stroke Benelli actually won the title but TD2 mounted Swede Kent Andersson was close behind in 2nd place at the end of the season. It marked the last time a four stroke would win the quarter litre class and the start of the production Yamaha twins reign as the privateer’s weapon of choice.
The machine seen here is actually a TD1B campaigned successfully by Don Padgett in 1967, when the new machine arrived for 68, Padgett’s quickly spotted that the latest chassis remained unchanged, with just the power plant coming in for major updates, thus they simply purchased a C spec motor and implanted it into the year old, and already well sorted, chassis
The power to weight ratio was so good that at one stage the Padgetts team taped strips of lead to the frame down tubes to stop the front wheel lifting during acceleration. It was also common to removed a length of the exhaust chamber to improve high speed revs and before too long many modifications had been developed to make the Yamaha even more competitive that when it left the packing crate.
Padgett Yamaha TD1C Specifications
- Engine – Air-cooled, piston port, parallel twin cylinder, 2-stroke
- Capacity – 247cc
- Bore & stroke – 56 x 50mm
- Compression Ratio – 8.10:1
- Carburetion – 2 x Mikuni VM30SC
- Max Power – 38bhp @ 10,000rpm
- Torque – 19ft-lbs @ 9500rpm
- Ignition – Hitachi magneto (Rex Caunt digital)
- Transmission – 6-Speed, wet clutch, chain final drive (5-speed std)
- Frame – steel twin loop
- Suspension – 32mm telescopic fork twin shock rear
- Wheels – 2.75 x 17, 3.00 x 18
- Brakes – 200mm twin-leading-shoe drum, 200mm single-leading-shoe drum
- Wheelbase – 1280mm
- Weight – 113kgs
- Fuel capacity – 21ltrs
- Top speed – 128mph
Padgett Yamaha TD1C Gallery