Power to the People
Story: Jim Scaysbrook
Photos: Dick Darby, Jim Scaysbrook, Sean Goldhawk, JMS archives
The stout little twin – the YD-1 – that Yamaha introduced in 1957 was a truly significant event in the fledgling company’s motorcycling history, but it was just the start of much bigger things. Admittedly, the design was very closely based (or even copied) from the German Adler MB250, down to having the clutch mounted on the end of the crankshaft rather than the gearbox shaft. Because there is no torque multiplication between engine and clutch, this allowed the clutch to be quite small, but it made for a fairly wide engine in the new Yamaha. What was to follow was a series of twin cylinder two strokes that would have the world really take notice of the tuning-fork brand.
The YD-1, prosaic as it may have looked, was a capable performer, as evidenced by its debut victory in race trim in the highly prestigious Asama Highlands race, which it followed up with an even more emphatic sweep of the major placings the following year. Back at the factory, the drawing boards were full of new designs, and across in the financial department, things were similarly happening at a feverish pace. Yamaha was on the acquisition trail, and one of their takeovers was the Showa brand, which had on its books a rather radical looking 250cc two-stroke single with a pressed steel monocoque style frame, leading link forks modelled on the British Earles design, electric starting and even tubeless tyres. Marketed as the Cruiser, the design became Yamaha property while Showa concentrated on the design and manufacture of suspension components and remains a major player in the field to this day.
Launched in July 1959 as the 250S, later renamed YDS-1, this new model was avant-garde, featuring a five-speed gearbox, a tachometer, and an early form of bikini fairing. This machine, probably the first Japanese motorcycle deliberately marketed as an out-and-out sports bike, set the course for a lineage that continued for decades and formed the basis for Yamaha’s Grand Prix domination.
In 1962, the even sportier YDS-2 arrived, with power boosted to 25hp and a beautifully styled twin-leading shoe front brake. Although visually similar to its predecessor, the YDS-2 engine and transmission were quite different, with virtually no interchangeable parts. In the Yamaha tradition, it was beautifully finished and as fast as some 500s. Privateer racers rejoiced when a proper racing version, the TD-1, was also released.
A Quantum Leap
Which brings us to the subject of our story, the ground-breaking YDS-3, which first saw the light of day in mid-1964. Once again, there was little visual change to discern, but the new model was a quantum leap. To cope with the extra power and torque, the gear teeth were widened, and a fifth plate was added to the clutch. The crankshaft diameter went up to 25.5mm and gudgeon pins to 20mm. Carburettors went from 20 to 24mm, providing a further boost in power. The frame was strengthened with forged engine mounting lugs, and the wheelbase was extended by 25mm. The front forks received stiffer springs and heavier damping for better handling when ridden hard. Other changes on the new model included revised instruments and warning lights.
However, the standout feature was initially dismissed by some as a gimmick, but it proved to be anything but. The need to pre-mix petrol and oil had long been a bugbear for two-stroke owners. Yamaha called their solution Autolube, and it did exactly what the name suggested. This system consisted of a variable displacement pump regulated by throttle opening, with the oil-to-fuel ratio varying from 200:1 at idle to 20:1 at full throttle. This meant the engine was always correctly lubricated, plug fouling was dramatically reduced, and exhaust emissions were slashed – a boon for the key market of California.
One quirk of the early Autolube system was that the pump was driven from the gearbox. This meant that when the motorcycle was stationary at traffic lights, held in gear with the clutch in, the pump ceased rotating. Until the clutch was released or neutral was selected, no oil was injected. Yamaha went to great pains to urge riders not to blip the throttle when stopped with the clutch in.
The YDS-3 received a rousing reception in Australia when it went on sale in late 1964. The acid test came at the Easter 1965 Bathurst Lightweight Production race. The previous year had been dominated by Hondas, but it was a different story twelve months later. From a standing start, Nick Rogerson equalled the class lap record on his YDS-3 and powered away to a 30-second win, finishing 10th on the road ahead of several big twins. The new Yamahas occupied the first five places. People still talk of the characteristic yowling noise, a combination of intake and exhaust, of the fleet of Yamahas on full throttle over the mountain.
A Rescue Mission
Around 1993, David Howe was operating an automotive business in Windsor, New South Wales. “The son of a customer,” David recalls, “came in one day and said that there was an old Yamaha sitting in the shed at home. It no longer ran after a late-life spell as a paddock basher. The oil pump had also been removed in favour of self-mixed petrol and oil, which led to the ‘not unexpected’ seizure.”
Rough as it was, the YDS-3 interested David, who parted with $300. “It sat in my mother-in-law’s shed for many years,” he says. “When she went into a nursing home, it had to come out, and I began to buy bits and pieces for it, which seemed to go on forever. It was all basically there, although the headlight and front mudguard were smashed, and everything was very rusty. It had been painted in a really garish gold/yellow metalflake paint, but underneath that, I found traces of the original red paint.”
One of the missing items was the oil pump. “I bought two YDS-5 pumps because I thought that would give me the pump and the oil lines, but none of it fits – the later pump runs in the opposite direction. Fortunately, Richard Steain had a correct pump, so that fixed that problem.”
Thus began a five-year restoration, with David doing most of the work himself, including the paint. He is quick to point out that the cylinder block is not the original cast iron version with nine fins, but a later alloy one with eight fins. “I am sure someone will point that out,” says David wryly.
Sparkling in the September sun on the banks of the Hawkesbury River, David’s YDS-3 made its public debut at the 2025 Macquarie Towns club’s annual Show Day, where it was awarded the perpetual Steve Thompson Trophy for the Best Japanese Motorcycle. Since then, it has been tuned perfectly, so from here on, expect to see the little red machine at plenty of rallies.
Specifications: Yamaha YDS-3 1964
| Engine | Two stroke, piston port, parallel twin. 180-degree crank in 4 roller bearings, needle roller small end and big end bearings. Light alloy cylinder head. Air cooled. |
| Bore x stroke | 56 x 50mm |
| Capacity | 247cc |
| Comp ratio | 7.5:1 |
| Lubrication | Autolube pump driven from gearbox, tank on right-hand side. |
| Power | 27hp @ 7500 rpm |
| Torque | 18.1 ft-lb 4.2 kgf-m @ 7500 rpm |
| Carbs | 2 x Mikuni VM24SC with air filter. |
| Ignition | Coil ignition. Kick start. |
| Electrical | Mitsubishi 65-watt DC generator charging 6-volt battery with automatic charging regulator. 6-inch headlamp. |
| Transmission | 5-speed. Helical gear primary drive. Wet clutch on left side crankshaft. |
| Final drive | Chain |
| Suspension | Front: Telescopic forks with hydraulic damping Rear: Dual shocks on swinging arm, 3 preload settings |
| Brakes | Drum front and rear |
| Tyres | Front: 3.00 x 18 Rear: 3.25 x 18 |
| Wheelbase | 1315mm |
| Wet weight | 145kg |
| Fuel capacity | 11.4 litres |
Gallery
