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Crosby Moriwaki Replica - Limited Edition - #9 of 10

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Moriwaki Monster - An especially built replica of the 1979 World TTF1 Championship Entry (3rd place) 1979 - Limited to 10 numbered units

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Bikes For Sale, Kawasaki

Description

Kawasaki Z1B Moriwaki review

Wild and vibrant roadster

4 cylinders in line, 1,135 cm3, 119 hp, 160 kg

It has been exactly 40 years since New Zealander Graeme Crosby entered the GP 500 as a factory Suzuki driver for the team led by British importer Heron Suzuki. He was only 24 years old! His arrival on the British racing scene in 1979 caused a sensation, because of the motorcycle he was riding, the very straight and non-faired Kawasaki Z1B Superbike with its high handlebars which had been prepared by the small Japanese company Moriwaki then unknown.

Remember, the Superbike discipline had only been invented in the USA three years earlier, with a first race contested in Daytona in 1976. This naked 4-stroke monster had not had time to migrate to Europe. Anyway, the British federation had invented the TT Formula 1 in 1977, with production engines prepared in a racing chassis, in order to save the world championship status of the Tourist Trophy. It also meant that American-style Superbike racing wouldn't have its place for a decade. So, at that time when the full fairing and the handlebars straps were considered to be de rigueur on a racing motorcycle, here is a New Zealander out of nowhere, sitting very straight on his Japanese road motorcycle, with no big cowlings other than a small bikini fairing on the front end came to face the local stars like Mick Grant and Ron Haslam who evolved them on the factory Honda. As one commentator pointed out at the time, "only a victory for a custom at the Senior TT would have made more noise!"

Moriwaki Kawasaki Z1B review
Moriwaki Kawasaki Z1B review

Genesis

Croz 'was one of the most versatile and talented pilots of his generation. He was also one of the most spectacular drivers the world has ever seen, making his mark on world-class road racing in just four years. He thus exploded on the international scene in 1979 riding this improbable Kawasaki superbike on which he finished between the two Honda by finishing second in the British TT F1 championship. This earned him a contract for the factory team Suzuki in 80/81 in 500 GP and TT F1, allowing him to win the TT F1 world championship and to win three times on the Isle of Man. Nothing less ! In 1982, he joined the Yamaha team newly formed by World Champion Giacomo Agostiniand won the Daytona 200 for its first race. But although he finished second in the championship that year, Croz was then discouraged by GP policy, so that he packed his bags and returned to New Zealand at the end of the season, withdrawing permanently from competition as its star was just beginning to shine in the Grand Prix galaxy.

Crosby on the Moriwaki Kawasaki Z1B during the 1979 Ulster GP
Crosby on the Moriwaki Kawasaki Z1B during the 1979 Ulster GP

Famous for his gimmick when he arrived on each new circuit, "which way is the track going and what is the lap record? ", Croz played his role of hero of the people. In addition to his regular wheelings which enchanted the crowd, his drifts from the back and his breathtaking overtaking, he was also noted for his spiritual replicas Combined with his carefree charm and his confidence, his sense of spectacle made him a pilot unanimously appreciated by fans around the world, with this ability to bring star pilots back to earth, both on and off. the track. His antics and gaiety reflected a seemingly nonchalant approach to racing, but one that actually masked the analysis of a fierce rival. Croz was running to win.

The history of road racing has known several iconic rider and motorcycle duos, such as Ago and the 3-cylinder MV , Mike Hailwood and his TT Ducati or even Mick Doohan on the Honda NSR500 . Graeme Crosby and the Moriwaki Kawasaki Z1 are on this list, especially after seeing him at work for most of the 1979 season, both from outside the track as a friend and a fan, but also closer was directly behind him on the starting grid of the TT F1 heats on my P&M Kawasaki.

I was lucky to be able to ride this bike on the Pembrey track in south-west Wales and thus answer a question I had been asking myself for 40 years: How well was the Moriwaki Kawasaki and what role did it play in Croz's rise to the top?

Graeme Crosby at the Festival of 1.000 Bikes in Mallory Park
Graeme Crosby at the Festival of 1.000 Bikes in Mallory Park

Discovery

Since the rules of TT Formula 1 limited the maximum displacement to 1,000 cm3 for the 4 stroke (and 500 cm3 for the 2 stroke), Mamoru Moriwaki could not use the Kawasaki Z 1000 introduced in 1977 as the basis for his TT F1 motorcycles . It had indeed a 1.015 cc engine. So he based the Crosby Superbike on the 1975 Z1B air-cooled engine., measuring 66 x 66 mm with a displacement of 903 cm3 with two overhead camshafts and mounted high compression pistons of 69.4 mm to reach 998.64 cm3 with a volumetric ratio of 11.5: 1. But when Gordon Pantall restored the engine, Moriwaki could not supply these pistons. He therefore mounted 74 mm Omega pistons on standard connecting rods, the cylinder being hollowed out to offer a final capacity of 1,135 cm3, or 14% more than on the Crosby version.

Kawasaki cube four-cylinder engine now at 1,135 cc
Kawasaki cube four-cylinder engine now at 1,135 cc

The eight-valve cylinder head with double overhead camshafts has been extensively reviewed by Moriwaki in Japan by being fitted with racing camshafts operating on oversized steel valves of 37.5 mm at intake and 31 mm at the exhaust, carrying robust springs via inverted horns from Z650. Although according to the TT F1 rules, Crosby was obliged to use the small Mikuni carburetors 28 mm road from the Z1B, for the races in Open class he mounted Keinhin CR of 32 mm race, which one still found on the machine today. An exact replica of the original Moriwaki 4-1 racing exhaust was purchased in Japan, with the exception of the aluminum silencer which replaces the original steel silencer. After encountering problems with the ignition of Pantall originally fitted a Dyna S electronic CDI powered by a 12V battery. The result is an engine that has been bench tested at 119 hp at 9,000 rpm. A Kawasaki five-speed short gearbox helps transmit this power to the ground via an original oil-bathed multi-plate clutch.

Keihin carburetors in the revised Z1B engine
Keihin carburetors in the revised Z1B engine

For the debut of the Moriwaki in racing during the 8 hours of Suzuka in 1979, this same prepared engine was mounted on a frame of Kawasaki Z1B modified with a hunting angle open of 2 ° additional compared to the origin for more stability . Triple T of Z650 were used, with a reduced offset for an elongated flush to 108 mm against the 90 mm stock. While changing the geometry of the steering, Moriwaki also stiffened the chassis with a bracing around the steering column and the front engine support. It is this same modified Z1B frame that is still present on the bike, with additional reinforcements. There is also a Moriwaki swingarm with two Kayaba shock absorbers 330 mm long adjustable on 9 preload levels.

Moriwaki modified shock absorbers are longer and more sloping than originally
Moriwaki modified shock absorbers are longer and more sloping than originally

These shock absorbers are much longer than the original components, they not only help increase the weight forward on the tire, but also offer additional ground clearance, crucial when combined with the large Moriwaki side covers of the motor. The fact that the upper shock absorber supports have also been moved further forward on the frame offers a semi-recumbent position which induces additional progressiveness for the suspension. The 36 mm Kayaba fork with pneumatic preload adjustment has a hunting angle of 28 °. The wide flat handlebar made in one piece is bolted to the upper triple tee by 40 mm bridges providing additional leverage. There is also a Kawasaki adjustable steering damper on the right.

The fork angle was opened at 28
The fork angle was opened at 28 °

The two 296 mm Kawasaki front brake discs in stainless steel remain the only characteristic of the Moriwaki which is constantly troublesome, easily overheating under the bite of AP-Lockheed two-piston calipers, whether on fast circuits like Silverstoneor slower like Scarborough. The 230 mm Kawasaki stainless steel rear disc with single-piston AP-Lockheed caliper ensures an additional slowdown essential to brake the 160 kg claimed dry by this racing bike, against the 232 kg of the Z1B! This weight is also made possible by the 18-inch Morris magnesium rims that have become extremely rare. Gordon Pantall bought them new via the Web when the motorcycle was restored. Their light weight also helps minimize the unsprung weight and therefore improves the tuning of the suspensions. These are fitted with vintage Dunlop racing tires with a KR125 3.50 / 3.25 on the 3 "front Morris wheel and a KR164 3.75 / 5.00 on the 4" rear.

The Moriwaki Kawasaki Z1B weighs only 160 kg when dry
The Moriwaki Kawasaki Z1B weighs only 160 kg when dry

Trial

The Moriwaki took a long time to start in the Paddock ... using the second gear! The first is indeed too low to be used elsewhere than at the start of a race. And this start-up was only done after having drowned the Keihin CR carburettors. Once warmed up, the engine then suffered a failure at high speed on the track, a problem solved by the replacement of a new 12v battery.

But once it runs, Moriwaki's prepared engine offers impressive acceleration for an eight-valve four-cylinder. This is also where the larger 32mm CR carburetors used for the Open category instead of the mandatory 28mm in TT F1 would have shown their interest on faster circuits.

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