1970 Kawasaki H1R 500

Kawi’s groundbreaking 2-stroke Grand Prix racer.

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by Phil Aynsley

Five decades ago a Grand Prix racer based largely on a street model finished runner-up in the 500cc world championship, prying open the door to eventual 2-stroke domination. That ground-breaking racer was Kawasaki’s 1970 H1R, a souped-up version of the Japanese manufacturer’s 1969 H1 road model.

The racer who finished second to Italian superstar Giacomo Agostini, as he swept to his sixth consecutive 500cc world title on MV Agusta’s pure GP racer, was tough Kiwi privateer Ginger Molloy.

His journey to the top echelon of GP 500cc racing started in the U.S. The Kawasaki H1R featured here is a remarkable time piece of originality from that impressive first year of racing.

An early convert to the potential of 2-strokes in the 500cc class, Molloy sourced one of the rare H1Rs available from a Florida dealership and first raced it in the 1970 Daytona 200. He finished seventh in a race where just 16 of the 98 starters reached the checkered flag.

A black motorcycle

The production model H1 “Mach III” had already established itself as a world-beater on the road. It wasn’t a bike for beginners. Powered by a 500cc, air-cooled 3-cylinder engine, the Mach III was nicknamed “The Widowmaker” because of its brutal power delivery and sketchy handling.

However, it had quickly made waves around the world in the popular production racing events, where it was challenging and often beating much larger 4-strokes. So it was perhaps inevitable that Kawasaki would make a Grand-Prix-spec version to enter the premier 500cc class.

Low numbers

Of the less than 50 H1Rs built by the factory over two years, most went to the U.S., as Kawasaki had targeted that booming sales market with the Mach III.

Kawasaki would sell 30,000 Mach IIIs worldwide in the first two years of production before the 750cc H2/Mach IV took over. This amazing sales result was underlined by the fact the 500cc would easily out-accelerate Honda’s new CB750 4-cylinder “superbike.” In standard form it even set a new 500cc world speed record at the Bonneville Salt Flats in 1969 of 117mph.

As well as blistering acceleration, the slim 3-cylinder engine, only slightly wider than Kawasaki’s smaller-capacity 250/350cc twins, gave it real potential as a GP 500cc racer. And it was cheap to buy, costing less than $30,000 in today’s money.

The Achilles heel was under-developed frame technology and the complication of keeping three air-cooled, 2-stroke cylinders singing at full revs in perfect harmony.

A closeup on a motorcycle part

Many decades later, Molloy gave New Zealand journalist Terry Stevenson an insight into how complicated the H1R was to set up for the grueling 200-mile Daytona race.

“On the first day I did a lot of carburetion checks,” he said. “They came out standard (from the factory) with the same jets in each carb but the right cylinder does the most work with the gears driving off it, and the middle one gets the hottest. I ended up with a 320 (main jet) in the right, a 315 on the left and a 310 in the center cylinder.”

Molloy’s tinkering had an instant effect.” After the first day my bike went through the speed trap at 159mph,” he said. Bear in mind that in 1968 top speeds were around 140mph and the 150mph barrier was only breached in 1969.

Looking forward

The future of 2-strokes as Daytona winners had been heralded in 1968 when Yamaha’s 350cc air-cooled twins finished second and third, then third and fifth in 1969. For 1970 the rules were changed at Daytona to allow any engine configuration up to 750cc to compete. This enticed exotic factory specials from Honda (CB750 4-cylinder) and Triumph/BSA (3-cylinder), as well as Harley-Davidson’s new overhead-valve XR750TT racer to enter.
While the H1R looked like a contender, it couldn’t match the sophistication of its Honda and Triumph/BSA rivals. For example, when Grand Prix veteran Ralph Bryans crashed early on and his Honda caught fire, it was obvious the engine had magnesium crankcases.

The secret to the H1R’s acceleration came through extreme cylinder porting and meticulous development of an expansion-chamber exhaust system to suit. This resulted in the distinctive crossover exhaust headers, which was the only way to ensure adequate cornering clearance.

A motorcycle

The robustness of the street engine meant standard connecting rods were used, after being slightly modified for increased oiling and cooling. Even the crankshaft was the same as the street model.

A pre-mixed petrol-oil ratio of 32:1 was backed up by an independent oiling system in which an adjustable pump fed directly to the crankshaft. A 2-ring piston, which made less power than an experimental 1-ring design, ensured reliability over GP-length race distances.

Strangely, a conventional battery, coil and points ignition was used rather than the road model’s CDI. However it was built from the highest-spec components, including platinum-plated contact points.

It would take another year for Kawasaki to work out how to get a CDI system to work at the sustained revs required in GP racing.

A motorcycle

Good results

Peak power was 75 horsepower at 9,000rpm, a remarkable figure for a 500cc engine at that time and some 15-20 horsepower more than the road model. Peak torque wasn’t far below peak power, making this a difficult machine to race compared to the 4-strokes of the period, despite having a close-ratio, 5-speed gearbox.

A dry clutch meant various experiments could be undertaken with gearbox oil additives. Randy Hall, who played a major role in Kawasaki’s race and road development in the U.S., says a 75-weight oil mixed with a friction modifier added another couple of ponies at the rear wheel.

A green motorcycle

He also says the first H1R frames were based on the smaller-capacity A1/A7-R racers’ double-loop chassis modified to fit the slightly larger engine and strengthened to help cope with the greater power output. Chassis strength and handling would remain an issue for Kawasaki over the next few seasons.

Rather than source brakes and suspension from European specialists, Kawasaki designed and manufactured its own, including the 250mm double-sided twin-leading shoe front brake.

Dry weight was a commendable 286 pounds compared to road model’s 383 pounds.

An indication of the potential for a Kawasaki victory in 1970 came with Texan Rusty Bradley’s win in the lead-up Daytona 100-Mile Junior race. However, at double the distance, the main event was a torture test.

While many of the big-name favorites dropped out, including Mike “the Bike” Hailwood, Molloy ignored fading engine performance to come in seventh. Dick Mann nursed his Honda to victory, closely followed by Gene Romero and Don Castro on factory Tridents. Canadian Yvon Duhamel finished fourth on his 350cc Yamaha 2-stroke twin, with rising New Zealand star Geoff Perry fifth on a Suzuki 500cc 2-stroke twin.

Going international

Molloy’s finish earned him enough money to take his Kawasaki to the European Grand Prix championship. However, he didn’t race it in the season opener at Germany’s Nurburgring, preferring to use his trusted and well-developed Bultaco TSS360 2-stroke single.

The reason was simple; the high-speed six laps of the 14-mile-long circuit would have required a fuel stop. Agostini won with Molloy gathering valuable points to finish fifth on his much slower Bultaco. (The sixth best results of the season would make up a rider’s championship points total.)

Back on the Kawasaki for the second round at Le Mans, France, Molloy finished second, 48 seconds behind Ago.
How fast was the Kawasaki on a true GP circuit? The three riders after Molloy were at least a minute behind Ago and the rest of the 17 finishers (from 37 starters) were lapped.

A green motorcycle

At the next round, the tricky Opatija circuit in Yugoslavia, Molloy discovered just how difficult it was to keep the Kawasaki at peak performance. “It blew the center carburetor off going up the hill,” he told Stevenson. “The ignition was firing badly. One day it would drive good, but the next day it wouldn’t.” That race involved 30 3.7-mile laps of a road circuit that ran around a seaside resort and up a nearby cliff-face. The veteran Kiwi, who had first come to Europe’s Continental Circus in 1963 aged 25 years, used all his race cunning to finish seventh behind Brit Dave Simmonds, another Kawasaki GP pioneer.

Agostini backed up his second win with victory at the Isle of Man TT, which Molloy sat out.

Molloy then finished fourth at the Assen round and second at Imatra in Finland. It was here that he finally sorted the ignition, replacing the standard points system with an electronic Krober. Being a privateer meant he didn’t have factory techs on hand to help, as he told Stevenson.

“We were camped by the road in the rudimentary pits and we had to find a lathe and put the ignition on,” he said. “We got it going just in time to go out in practice and the bike was very lively, a totally different bike!”

Ago was imperious at the Monza round, where he and teammate Angelo Bergamonti lapped the entire field to finish first and second. Molloy crossed the finish line in sixth place but proof of how many riders were now recognizing the winning potential of the H1R is shown in the results. Kawasakis filled seven of the top 10 with a Paton 4-stroke twin splitting them in seventh.

Undefeated in all his races that season, Ago sat out the final at Spain’s 2.3-mile Montjuic street circuit in Barcelona. Bergamonti beat Molloy by nearly two minutes but the Kiwi was the only rider not to be lapped.

His championship runner-up position was determined by his four podiums, a fourth at Assen and fifth at the Nurburging.

A black and white photo of a motorcycle rider

French rider Christian Ravel finished eighth at Montjuich to end up seventh in the championship standings and the next best-placed Kawasaki rider behind Molloy. The H1R featured here has a link to Ravel’s family as it belonged to the French Kawasaki importer Xavier Maugendre (SIDEMM) from 1972 to 1975. It was ridden by several top riders, including Ravel’s brother Didier and Rene Guili.

The 500cc engine was replaced with a 750 H2R triple and raced in various high-profile European events before going into hibernation for 20 years before French collector and Kawasaki enthusiast Francis Taillefumier acquired it.
It came with the original 500cc engine and parts so he was able to restore it to original specification. Only the fairing had to be reproduced. Even the original shock absorbers were serviceable. It is fitted with electronic ignition from the 1971 model, but the original is still an option, complete with platinum points.

The owner has ridden it in demonstrations at European classic festivals, confident that he has enough spares to keep it running. These even include a spare crankshaft with its distinctive specialist bearings with orange seals that prevent them from turning in the crankcase. Taillefumier describes his H1R as “not easy to ride, but it is a fantastic machine!”

But what of Molloy? He moved to the U.S. in 1971, where the racing scene there paid far more than the European GP scene.

Later races

Kawasaki had proved that it was possible to transition development of a 250/350cc 2-stroke into a GP contender, but it was yet to become a race winner.

The next year another Kiwi privateer finished second, this time on a Suzuki twin. Like Molloy, Keith Turner’s points score included podiums but no race wins. However, improvements made for the 1971 H1R helped Dave Simmonds give Kawasaki its first premier-class win. That was at the season finale at Jarama, Spain, which Ago didn’t attend, having already won the title.

A motorcycle rider

Ago won the world title again in 1972 but by 1974 had switched to purpose-built GP-spec liquid-cooled 4-cylinder 2-strokes built and supplied by Yamaha. Like Molloy, his journey started at Daytona, which he won first time out. His 1975 500cc world title on a Yamaha was the first in a long-line of championship wins for Japanese 2-strokes.

But the first steps towards 2-stroke domination began in 1970 at Daytona, when a largely road-based H1R 500cc triple hit 159mph and survived 200 miles at peak revs in the hands of a privateer racer. MC


About the Owner

Francis Taillefumier’s first ever motorcycle was a Kawasaki KH 400 he bought from the French importer Xavier Maugendre (SIDEMM) who had come to buy champagne from his parents’ vineyard. Later he owned 500cc and 750cc versions of Kawasaki’s triples. At left is Francis (black leathers) at Spa Francorchamps with Mick Grant, who rode a water-cooled version of the H1R, called the H1RW, to victory at the 1975 North West 200 in Ireland and the 1975 Senior race at the Isle of Man TT.

Two people next to motorcycles

“Motorcycle racing has always been my passion and 18 years ago I looked for the H1R,” he says. “It is one of the most beautiful racing motorcycles and at the time it was challenging Giacomo Agostini with French riders.” His acquisition resulted in friendships developing with former Kawasaki racers, including Jean Francois Baldé. Taillefumier has also bought a lot of parts on the internet from around the world to keep his H1R going.

  • Updated on Feb 7, 2022
  • Originally Published on Feb 3, 2022
Tagged with: Kawasaki
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