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Bimota YB6 Tuatara

|
Make Model |
Bimota YB6 Tuatara |
|
Year |
1990 |
|
Engine |
Liquid cooled,
four stroke, transverse four cylinder, DOHC,
5 valves per cylinder. |
|
Capacity |
1002 |
|
Bore x Stroke |
75.5 x 56 mm |
|
Compression Ratio |
12.0:1 |
|
Induction |
Weber-Marelli Fuel
injection |
|
Ignition /
Starting |
Digital / electric |
|
Max Power |
145 hp @ 10500 rpm (rear
tyre 127.3
hp @ 10600 rpm) |
|
Max Torque |
9.6 kg-m @ 9000 rpm |
|
Transmission /
Drive |
5 Speed / chain |
|
Frame |
Two diagonal beams in section bar made of
aluminium with internal ribbing. The cylinders are supported by plates
bolted to the beams and the swing arm is made of aluminium |
|
Front Suspension |
Marzocchi inverted telescopic forks, 3-way
adjustable compression and rebound damping |
|
Rear Suspension |
Marzocchi monoshock, adjustable compression
and rebound damping |
|
Front Brakes |
2X 320mm discs |
|
Rear Brakes |
Single 230mm disc |
|
Front Tyre |
120/70 ZR17 |
|
Rear Tyre |
180/55 ZR17 |
|
Dry-Weight |
168 kg |
|
Fuel Capacity |
20 Litres |
|
Consumption average |
15.3 lm/lit |
|
Braking 60 - 0 / 100 - 0 |
13.3 m / 35.9 m |
|
Standing
¼ Mile |
10.4 sec / 213.1 m |
|
Top Speed |
279.4 km/h |
|
The Tuatara is a special
version of the YB6. It differs chiefly by the introduction of fuel injection
rather than carburettors. The name Tuatara comes from the name of a reptile
in New Zealand, which moves exceptionally slowly. |
Bimota's Tuatara is easily the most expensive and
exclusive production motorcycle. It's also arguably the fastest. Production
at the small Bimota factory in Rimini was limited to just 60 examples. These
were built in response to customer demand for a bike with performance
'superior to a World Superbike racer.' Bimota already had a stable of pretty
quick and rare machinery to choose from - like the YB4 racer that had won
the 1987 Formula-One World Championship and is easily capable of 160mph
plus. Then there was the YB8, a Yamaha FZR1000 Exup-based street bike,
normally carbureted, making and 170mph. But no, these rich customers wanted
something more, something faster still. Bimota looked at their dyno figures
and concluded it was possible. They would build 60 ultimate road bikes
selling them at a price befitting their exclusive status.

They chose as a suitable powertrain for the world's fastest motorcycle
Yamaha's original FZR1000 - the 989cc unit that preceded the increased bore
FZR1000 Exup version of 1003cc. Remarkably, Bimota did little to liberate a
big increase in horsepower from the stock engine. They merely fuel-injected
it, and fitted their own less restrictive and lightweight stainless steel
exhaust. By concentrating solely on efficient induction and exhaust
scavenging, Bimota's engine tuners were rewarded with a peak of 152hp at
9500rpm.
The motor's top end grunt was simply enormous. Meanwhile the
chassis engineers worked wonders in wedging a large engine into a frame and
running gear no larger than that used on a 600cc bike. Indeed, the l000 cc
Tuatara weighs only 3kg more than Bimota's 600cc Bellaria. The weight saving
exercise begins with a twin-spar aluminium frame, and continues with
lightened inverted Marzocchi forks hand-laid carbon-fibre and fibreglass
bodywork right through to the magnesium alloy wheels. To save weight around
the steering head they replaced the traditional instrument cluster with a
slim, electronic digital panel. The wheelbase is a tight 56in. The
power-to-weight ratio is as keen as anything on two wheels, racers included.
Beautifully finished and styled and well up to Bimota's usual high standards
of quality, the story goes that the factory test rider, Giancarlo Falappa,
took the bike speed testing along a deserted Bologna-Ancona motorway at 5am
one bright morning. On perfect gearing and after some fine-tuning of the
fuel injection system, the factory bike was timed at 300kph or 187mph -
which makes it the fastest production road bike in the world - bar none.
Attempts to duplicate that speed on the few models made available for
testing have proved impossible. Although all 60 Tuataras made were
hand-assembled, the factory bike does seem to have been a bit special. A top
speed of 175mph appears nearer the mark for the 60 that were released.
At 175 or 187mph there's no denying the Tuatara is
indecently quick. It gets its name from an exotic greenish-grey lizard found
only on small islands around New Zealand. They have been around for 225
million years, when the pace of life was definitely a little slower.
Source: The worlds fastest motorcycles by
John Cutts & Michael Scott |