1968 Yamaha TD1-C November 8, 2006
There was no doubt that Yamaha got a few things wrong with its first production racers, the TD1-A and TD-1B. The ‘B’ went some way towards correcting these, with a larger 25mm crankshaft and a porous chrome plating applied to the cylinder bores to retain oil and increase engine life. With changes to port timing, the engine now revved to 10,000 and gave better all-round performance, but there were still reliability problems. Engine mounts cracked, the clutch was still a very fragile affair and the chrome cylinder lining would flake off, snagging the rings. However the TD1-C, announced for the 1967 season, was represented a quantum leap in the vital missing ingredient – reliability.
The engine design was all-new and was based on the YDS3. Significantly, the enormously troublesome clutch, which now had three extra plates, had been moved from the crankshaft to the gearbox countershaft – the bane of the earlier design. Without the weight of the clutch on the crankshaft, the engine’s power characteristic and its longevity were much enhanced. The jumble of cogs inside the gearbox was also reorganised, with the huge gap between first and second narrowed considerably and the other ratios altered to suit. Each cylinder lining now incorporated a ‘boost finger’ running up either side of the inlet port with corresponding windows cut into the piston. Thinner piston rings and substantially altered inlet and exhaust porting pushed the power up to almost 40 bhp. The cycle parts from the TD1-B were basically retained, including the distinctive teardrop-shaped petrol tank.
This particular machine was bought new by Perc Howard, who had campaigned a 125cc Bultaco TSS with some success. However the saddle was soon occupied by the top NSW rider of the day, Ron Toombs, who brought with him some sponsorship from Shell. One of the first outings for the new Yamaha was the NSW Grand Prix at Catalina Park, Katoomba, where the versatile Toombs, who rode four different machines at the meeting, won the Lightweight GP from Ray Curtis’ Suzuki and Kevin Fraser’s Bultaco. Howard took over the bike for the Victorian GP at Phillip Island in January 1968, scoring fifth place in the Lightweight, but Toombs was back aboard to take second behind Dick Reid’s AI-R Kawasaki at the Australian TT at Mallala one week later. Toombs lost this race after running off the track at the end of the main straight and was highly critical of the Yamaha’s front brake, which tended to fade badly in longer races. With the all-important Bathurst meeting coming up, With a little help from Shell, Toombs purchased the Yamaha from Howard and Ron’s friend and race engineer Tony Henderson began to make a few changes. The most noticeable was the fitting of twin Lockheed front disc brakes – a mod also made by Bill Horsman to his Manx Norton.
There were plenty of TD1-Cs on the grid at Bathurst. Besides Toombs’ lurid yellow machine, South Australian Peter Richards, and Victorians Allan Osborne and Josh Lange all had new Yamahas. It made little difference to Ron, who battled with Horsman’s Bultaco before clearing off to win. Within twelve months however, the TD-C was itself rendered obsolete by the sensational new TD2 (250) and TR2 (350) Yamahas, and this machine was old to Wollongong rider Geoff Sim. Geoff raced the bike at Bathurst in 1970 and later took out two Australian 125cc titles.
The ex-Toombs TD1-C (engine number 000200) has been beautifully restored in its original Shell colours by Richard Johnson and has been loaned by Sim to the National Motor Racing Museum.
http://www.ma.org.au/
There was no doubt that Yamaha got a few things wrong with its first production racers, the TD1-A and TD-1B. The ‘B’ went some way towards correcting these, with a larger 25mm crankshaft and a porous chrome plating applied to the cylinder bores to retain oil and increase engine life. With changes to port timing, the engine now revved to 10,000 and gave better all-round performance, but there were still reliability problems. Engine mounts cracked, the clutch was still a very fragile affair and the chrome cylinder lining would flake off, snagging the rings. However the TD1-C, announced for the 1967 season, was represented a quantum leap in the vital missing ingredient – reliability.
The engine design was all-new and was based on the YDS3. Significantly, the enormously troublesome clutch, which now had three extra plates, had been moved from the crankshaft to the gearbox countershaft – the bane of the earlier design. Without the weight of the clutch on the crankshaft, the engine’s power characteristic and its longevity were much enhanced. The jumble of cogs inside the gearbox was also reorganised, with the huge gap between first and second narrowed considerably and the other ratios altered to suit. Each cylinder lining now incorporated a ‘boost finger’ running up either side of the inlet port with corresponding windows cut into the piston. Thinner piston rings and substantially altered inlet and exhaust porting pushed the power up to almost 40 bhp. The cycle parts from the TD1-B were basically retained, including the distinctive teardrop-shaped petrol tank.
This particular machine was bought new by Perc Howard, who had campaigned a 125cc Bultaco TSS with some success. However the saddle was soon occupied by the top NSW rider of the day, Ron Toombs, who brought with him some sponsorship from Shell. One of the first outings for the new Yamaha was the NSW Grand Prix at Catalina Park, Katoomba, where the versatile Toombs, who rode four different machines at the meeting, won the Lightweight GP from Ray Curtis’ Suzuki and Kevin Fraser’s Bultaco. Howard took over the bike for the Victorian GP at Phillip Island in January 1968, scoring fifth place in the Lightweight, but Toombs was back aboard to take second behind Dick Reid’s AI-R Kawasaki at the Australian TT at Mallala one week later. Toombs lost this race after running off the track at the end of the main straight and was highly critical of the Yamaha’s front brake, which tended to fade badly in longer races. With the all-important Bathurst meeting coming up, With a little help from Shell, Toombs purchased the Yamaha from Howard and Ron’s friend and race engineer Tony Henderson began to make a few changes. The most noticeable was the fitting of twin Lockheed front disc brakes – a mod also made by Bill Horsman to his Manx Norton.
There were plenty of TD1-Cs on the grid at Bathurst. Besides Toombs’ lurid yellow machine, South Australian Peter Richards, and Victorians Allan Osborne and Josh Lange all had new Yamahas. It made little difference to Ron, who battled with Horsman’s Bultaco before clearing off to win. Within twelve months however, the TD-C was itself rendered obsolete by the sensational new TD2 (250) and TR2 (350) Yamahas, and this machine was old to Wollongong rider Geoff Sim. Geoff raced the bike at Bathurst in 1970 and later took out two Australian 125cc titles.
The ex-Toombs TD1-C (engine number 000200) has been beautifully restored in its original Shell colours by Richard Johnson and has been loaned by Sim to the National Motor Racing Museum.
http://www.ma.org.au/
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