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Bimota YB9 SR

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Make Model |
Bimota YB9 SR |
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Year |
1994 |
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Engine |
Liquid cooled, four stroke, transverse four
cylinder, DOHC 4 valves per cylinder. |
|
Capacity |
598 |
|
Bore x Stroke |
62 x 49.6 mm |
|
Compression Ratio |
12.0:1 |
|
Induction |
4x Keihin CKVD36 carbs |
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Ignition /
Starting |
Digital / electric |
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Max Power |
100 hp 72.9 kW @ 11500 rpm |
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Max Torque |
65.7 Nm @ 9500 rpm |
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Transmission /
Drive |
6 Speed / chain |
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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 |
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Front Suspension |
41mm Paioli upside down forks, 22 possible settings in
compression and 24 in extension adjustable. |
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Rear Suspension |
Paioli monoshock preload, rebound and bump
adjustable. It is
also possible to adjust the wheelbase by +/- 5 mm. |
|
Front Brakes |
2x 320mm discs 4 piston calipers |
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Rear Brakes |
Single 230mm disc 2 piston caliper |
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Front Tyre |
120/70 ZR17 |
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Rear Tyre |
180/55 ZR17 |
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Dry-Weight |
175 kg |
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Fuel Capacity |
16 Litres |
To the Latin
way of thinking a Bimota YB9 is a perfectly logical motorcycle. Only a nutcase
would settle for anything less than perfection, right? Yep, the YB9 was one of
the best bikes Bimota ever made, with the FZR600 Yamaha engine powering a lithe
handling, sharp braking masterpiece on wheels. Sheer Latin class.
Then they went
and made it even better, in the shape of the Thundercat engined YB9sri, which
featured a fuel injected, wailing banshee of a motor.Just one slight problem.
The YB9 cost around £13,000. Oh well, back to the Superdream 250 and the lottery
scratchcardsIt wasn't quite the introduction I'd intended. On arriving at
Bimota's launch in the south of France, I'd planned to start the day by taking a
bike I was already familiar with for a few fairly gentle exploratory laps,
before attacking the twisty, Armco-lined and slightly intimidating Le Luc
circuit in full go-for-it track-testing mode on the new YB9 SR, the one model
present that I'd not yet ridden.

But things didn't work out quite like that.
Instead, I turned up to find that one of the two YB9s that Bimota had brought
had been written off in a crash the day before. And that my first short session
on the sole survivor was right now, with no time for a warm-up and no guarantee
that the little yellow machine would still be in one piece when my turn came
round again later in the day.If I felt under a bit of pressure shortly
afterwards, as I snapped my dark visor shut, knocked the YB9 into gear and
accelerated down the pit-lane, then it didn't take Bimota's newest star long to
blow any worries clear out of my mind. A few minutes later I was winding the
throttle back to the stop out of a long right-hander, snicking into fourth gear
on the next short straight, and then holding the YB9 flat-out through the
following curve engine revving crisply, horizon tilted severely, right knee
planted on the ground and the Speedo indicating just over 100mph.If that sounds
like a tiresome tale of bravado, then precisely the opposite is intended.
Far
from enjoying pushing my luck on dangerous and unfamiliar racetracks, I‚have
always treated places like Le Luc with a caution deserving of a thick
YB9-coloured streak up the back of my leathers. Yet the Bimota inspired such
instant and total faith in its reserves of handling ability, grip and ground
clearance that this high-speed attack on a bike I'd barely met wasn't a big deal
in the slightest.Such refined racetrack behavior was to be expected, given that
this Bimota, powered by Yamaha's latest FZR600 motor, is a development of the
old FZR-engined Bellaria model (which was also designated the YB9). Although
designed as a two-seater and rather soft and gentle by Bimota standards, the
Bellaria was still ruff 'n tuff enough to win two Italian supersport titles in
the hands of the Rimini firm‚s development rider Gianluca Galasso. The SR shares
the Bellaria's familiar twin-spar alloy frame design, which can be traced back
all the way to Virginio Ferrari's 1987 world Formula One championship-winning
YB4, but almost every other component is new. Even the frame has not escaped
attention completely, its steering head angle having been steepened slightly to
give rake and trail figures of 24 degrees and 93mm. The steel rear sub frame has
also been modified, and is claimed to be both lighter and stiffer.Suspension is
totally new. Bimota's familiar milled alloy yokes hold 41mm Paioli forks whose
sliders are also machined from solid billet, rather than cast, for extra
strength. All compression damping is handled by the left leg and all rebound by
the right, which increases hydraulic efficiency although it inevitably
introduces twisting forces into the system. The carbon-fibre front mudguard is
built extra-thick in the middle, to add rigidity by acting as a brace.Another
novel front-end feature is the floating bearing in each fork leg.
These bearings
can move backwards and forwards up to 0.7 degrees, theoretically improving the
fit between stanchion and slider under the inevitable flex that occurs
particularly under hard braking. Bimota is resigned to using telescopics rather
than its own Tesi front end for the immediate future, but in the meantime is
making every effort to minimise the system's inherent drawbacks.Rear suspension
is also by Paioli, and works a new alloy swing-arm that is slightly shorter than
the Bellaria's as well as being stiffer and lighter. Wheelbase is adjustable by
15mm (ride-height can also be fine-tuned by adjusting the shock length by up to
5mm), and is nominally just 1380mm, 35mm shorter than that of the standard
FZR600. The Bimota's 175kg dry weight figure gives a 9kg advantage over the
standard Yam, too. Even by 600cc class standards, this is one seriously small
and light motorbike.At 810mm its seat is quite high, and the footrests are very
high, positioned to give unlimited cornering clearance at the expense of
severely folded legs.
There‚s a fair stretch forward to handlebars, which offer
a certain amount of adjustability though not much because they're bolted below
the top yoke, and the surrounding area is taken up not just with the fairing,
but also with the air-ducts that lead back from its nose to the under-tank airbox.Those ducts help give the front-end a suitably mean look, and the whole
bike is very smoothly shaped, in contrast to the rather slabby looking Bellaria.
The tank-seat unit is a particularly neat piece of styling, especially in its
dramatically waisted tail section. This bike is much less accommodating than the
Bellaria, though it does have a thin pillion perch that can be bolted in place
of the normal seat-hump.Bimota had use of Yamaha's new water-cooled motor almost
before the FZR was in the showrooms, so somebody in Rimini must be pulling a few
strings. (It's probably no coincidence that Bimota managing director Walter
Martini was previously general manager of Italian Yam importers Belgarda). The
16-valve lump is totally unmodified, though its Keihins are rejetted to suit a
new airbox and four-into-one exhaust system.
Bimota originally claimed this had
given the prototype a few extra horses, but the production YB9‚s claimed peak
output of 100bhp at 11,500rpm is identical to that of the stock FZR. So too is
the delivery all the way through the range. Like many a 600cc four, the Yam
motor thrives on being caned to within a gnat‚s of its redline but at low revs
is as flat as last night's half-finished bottle of Lambrusco.

You can pull away
gently yet cleanly with just 3000rpm showing on the tacho (clocks are also
borrowed from the FZR). But acceleration is mediocre even from twice that engine
speed, and for serious progress the needle must stay above eight grand.Not that
this was a problem at Le Luc, where the Bimota's light throttle, slick gear
change and impressive smoothness made keeping the motor on the boil both easy
and enjoyable. Trickiest part of the track was a left-right-left sequence
followed by a long and slightly downhill right-hander. Happily the Bimota would
just about pull all the way through in one gear, leaving the pilot to
concentrate on grip and steering. Then it was throttle open and helmet behind
the tinted screen to devour the fastest section of the circuit, in a vain
attempt to reach the YB9's top speed of about 150mph. Even most Bimota pilots
would doubtless be happy enough with that level of top-end performance, and with
the right rider the Nine was the quickest bike around Le Luc's twists and turns.
As with any 600, though, the lack of midrange overtaking punch would be much
more tiresome on the road.Whether on road or racetrack, you could hardly fail to
appreciate the YB9's lightness and brilliantly agile handling. Stability at
speed goes almost without saying. The bike felt as solid as a lump of Provencal
granite (ever tried putting in a tent-peg at nearby Paul Ricard?) both in a
straight line and through the aforementioned flat-out right kink, which would
have been much more of a test of bottle on any other 600 you could name.
Steering was light, neutral and very precise, with the hands-down, bum-up riding
position aiding control and putting plenty of weight over the front wheel. I was
impressed with the forks, which were firm enough to keep brake dive to a minimum
yet compliant enough for plenty of feedback (though I wouldn't particularly want
to sample them in Dalston High Street). If there was the slightest twisting in
the system due to the legs‚ opposing damping forces then I couldn't feel it,
even when the familiar front-brake combination of four-piston Brembo calipers
and 320mm drilled discs was used to the full.
The Paioli shock also did a good
job, keeping the back end under excellent control despite the forces being fed
into it by the ultra-grippy 160/55-section rear Hi-Sport. Maybe the shock seemed
a fraction soft through the slight dip coming out of the circuit's final slow
right-hander, but that didn't feel like anything that a little adjustment
couldn't cure. (Talking of adjustment, one hack was surprisingly critical of the
YB9's handling before admitting he'd been trying to fine-tune the forks with the
choke knob, set in Bimota's normal position on the top yoke. At least he hadn't
slagged the motor for running too rich...)The only things I could seriously find
to complain about, mediocre midrange apart, were the high footrests that made my
legs ache after just 20 minutes. In a way, it's the radical riding position that
best sums-up the YB9. In contrast to its predecessor the Bellaria, which
ironically was arguably more comfortable than the standard Yam, this is a hard,
fast, no-compromise sportster in traditional Bimota mould. The Rimini factory
hasn't yet produced enough bikes to make it eligible for racing outside Italy,
but when that happens it will almost certainly clean up.So it should, of course,
considering that the market for Japanese 600s is so price-sensitive that most
have steel frames and few fancy details. Bimota doesn't have the same concerns,
but is making a big effort to keep prices down even so. At £9999 the YB9 costs
half as much again as any mass-produced 600, but this is by far the cheapest
Bimota. And maybe ten grand isn't so expensive for a hand-built machine that
brings a new level of speed, style and exclusivity to middleweight motorcycling.

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