Two plus four equals drama
Two-stroke engines are banned from motorcycle Grand Prix racing. It’s an industry thing: when Japanese manufacturers stopped making two-strokes a decade or so ago, due to increasingly stringent emissions regulations, 990cc four-stroke MotoGP bikes replaced the original 500cc allcomers category and two-strokes were written out of the sport.
By that time they had dominated for half a century, first in the smaller classes. It took until 1975 – 40 years ago – for two-strokes to conquer the premier 500cc category.
Until then four-strokes were supreme in the class of kings or, to be precise, Italian rider and sometime movie star Giacomo Agostini reigned supreme aboard his MV Agusta, the aristocratic Italian marque that had remained unbeaten for 17 seasons. Owner Count Domenico Agusta bankrolled his race team with the profits from building Agusta Bell military helicopters.
Meanwhile Ago enjoyed the dolce vita, “to race and skid and crash and then make love and drink wine”, as one journalist put it at the time.
However, the writing was on the wall, although Ago initially resisted the advances of top two-stroke brand Yamaha. “In 1971 I thought it was too early to race a two-stroke – the engines kept seizing,” he says. “But eventually I could see that two-strokes were getting faster and safer, while it was difficult to find more power from the four-stroke.”
In 1973 Yamaha entered the 500 class with its four-cylinder OW19. Its genius rider Jarno Saarinen ran away with the first two races – Ago crashing out at Paul Ricard trying to stay with him – only to lose his life at Monza, ironically, through the two-stroke curse. Renzo Pasolini’s Harley-Davidson two-stroke locked up in front of him, killing them both.
Yamaha withdrew for the remainder of 1973, then successfully courted Ago for 1974. Agostini knew he needed a two-stroke but he also wanted to get away from MV’s new race chief, arrogant playboy ‘Rocky’ Agusta, and MV team-mate Phil Read. The relationship between Ago and the Briton was so soured that someone put a Read sticker in the race-shop toilet bowl.
Agostini tested the new Yamaha OW20 at the factory’s Fukuroi test track in Japan.
“He told the engineers the steering head was too steep – the bike was shaking its head,” remembers Yamaha’s Rod Gould, who had signed Ago. “The next day he rode it again. Ago said, ‘It’s much better now, what did you do?’ They’d made a new frame. He asked how. ‘Well, there’s 24 hours in a day’, they replied. Ago was amazed; that would have taken a month at MV.”
And yet the relationship wasn’t an immediate success. Engine seizures continued to plague Yamaha in 1974, despite diligent work by Ago’s crew. “We used to crosshatch all the pistons with sandpaper, so they’d be smooth but not too smooth, because they needed to carry the oil,” recalls mechanic Mac Mackay.
The OW20 also glugged fuel at the rate of 11mpg, so it needed 43 litres – most of it in the fuel tank, some in the seat unit – to finish at Spa-Francorchamps. And each change of gear ratio – to help keep the engine within its 2000rpm powerband – required a full five-hour engine strip.
“You’ve no idea how many all-nighters we did at races,” adds Mackay. “A couple of the mechanics got pleurisy [a nasty lung condition], just through overwork. It was murderous.”
The OW26 of 1975 was much improved. It was even faster, drank less fuel, weighed 20 kilos less, had a cassette gearbox and handled better, thanks to monoshock rear suspension.
The 1975 campaign was a classic: a summer-long duel between Ago on the Yamaha and Read on the MV, two-stroke versus four-stroke, Europe verses the East, debonair Italian versus British rocker rebel.
Ago made a perfect start, defeating Read by 29 seconds at the Ricard season-opener. Then things went awry. He suffered a puncture and a couple of mysterious seizures that put Read ahead, against the odds. Ago took the title at the last round by just eight points, so finally the two-stroke was the undisputed king of motorcycle Grand Prix racing.
“As a rider, Ago was a bit over the hill by then,” adds Mackay. “But his determination to beat the MV made up for that, plus his intelligence: he could get the best out of the bike.
“It was brilliant working for him because he wanted to know everything and showed real interest. And if we had to work through the night he would never go to bed without organising someone to come in with sandwiches and coffee at one in the morning. It was a real tight team, everyone helped everyone else. And [race chief Masayasu] Mizoguchi never left us, even if we worked till 5am.”
The two-stroke’s reign continued until 2002, when 990cc four-strokes were introduced to take on the 500cc two-strokes, which were then phased out, while the 250s were replaced by Moto2 and the 125s by Moto3.
Barry Sheene was the last Briton to win a motorcycle GP world title, way back in 1977, but it looks like those four decades of hurt may finally be over, thanks to Danny Kent.
The Wiltshire 21-year-old has amassed a huge points lead in the madcap 250cc Moto3 class. Getting the best out of these 60hp 150mph four-stroke singles requires flawlessly smooth riding and cunning racecraft.
Multi-rider skirmishes are the norm, with the top five or six usually separated by about half a second at the flag. Kent’s ability to be in the right place at the right time is uncanny.