
It's a brand new model in Japan, launched at the 1990 Japanese
GP amid a clamouring swarm of Kushitanied Jap youth ('tasty riders' as they call
themselves). The frame is like nothing anyone has seen before, and the engine,
although ostensibly a smallbore CBR600, has a new aspect to us in the UK in that
it has gear-driven cams, like the VFR V-4s. Whether we see it here next year
probably depends on how well the VFR400R (NC30) sells in the UK this year. I
doubt Honda UK have even heard of it. Yet.
The styling precurses the NR750, the bike to carry the mantle of
the RC30, which we may see launched in the autumn. It's as if the CBR has been
frozen midway through an RC30-NR750 metamorphosis. The front end looks
conventional RC30, then halfway down the wide-section aluminium frame beams it
stops, as if sawn in half, and begins a curvaceous, multi-planed meld of cast
aluminium, through to the 'gull-arm'.
The engine is a stressed member, mounted at cylinder head and
gearbox. In effect, Honda have wrapped the frame around the engine, wholly
integrating it with the chassis, retaining a very strong head stock, low C of G,
and creating a wasp-waist for low seat height and to allow the rider to tuck
right in. The laid-down rear shock, reminiscent of a Yamaha TZ racer, assists
the low profile. There's even a little badge on the frame behind the clutch
cover which says 'LCG' — standing for Low Centre of Gravity.
And the gull-arm? Well, besides looking like all the current
Grand Prix 500s and therefore trendy, has it any real benefits?
For the GP racers, the gull-arm is an answer to exhaust pipe
accommodation problems. In the quest for more power, exhaust shape is crucial
and the frames have been built around them for the sake of a better engine. One
side looks conventional in wide section ally, but is heavily braced along the
top in what appears to be cast aluminium, webbed for strength and lightness, to
make up for what must be the inherent weakness of the bent arm on the other
side.
I asked Lester Harris of chassis builders Harris Performance
what he thought the benefits were to chassis design and handling of a gull-arm.
"From a purely technical standpoint, it's not necessary," says
Lester. "Chassis design is inevitably a compromise when you have an engine and a
rider to consider and on the GP bikes the gull-arm is necessary
for the routing of the exhaust pipes. On a road bike its largely
a styling exercise." He went on to say that on the other hand, four exhaust
pipes present a major problem too so there may well be some ground clearance
benefits.
More likely, it's just another fashion accessory. Nevertheless,
it goes to make the bike look like no other, which is reason enough for
manufacturers and punters alike.
The engine is a little peach. Of interest to us in the UK is the
gear-dnven cams which we've only seen on the vee-fours until now. The advantages
are precise cam timing and trouble-free cam-drive; chains, belts and tensioners
have always been a source of niggly hassles. Here, you can hear the gears
trilling away within the block.
Besides this, the motor appears much like a CBR600: a DOHC
16-valve in-line four. The carbs are 26mm CV flat-sides angled to give maximum
downdraft with a reasonably straight shot through the combustion chambers. The
au box is huge taking up most of the front of the petrol tank space, with air
ducted from the front of the fairing
On V&M Racing's dyno, it produced the same horsepower as the
VFR400R (NC30) — 57bhp, a gnat's-nob less than claimed on the Japanese spec
sheet. The VFR400R has more horsepower right through the range, though — as much
as lObhp at 9000rpm. The VFR out-torques the CBR too, producing 26ft-lb at its
peak (9750rpm) compared to the in-line four's 22ft-lb at 12,750rpm. The CBR
comes back on the VFR beyond 13,500rpm (eek!).
Nevertheless, Jack Valentine at V&M was well impressed with the
torque curve. It's dead flat from 9000rpm right through to 15,000rpm,
which is, amazingly, where peak power is produced. The horsepower rises in
proportional increments with the revs from 6000rpm, where the dyno starts
measuring the output, up to 13,000rpm where the curve flattens out. It's rare to
see such a progressive power curve.
The riding experience bears out the test-bench. The gutsy little
motor picks up smartly from 4000rpm and pulls right through to a screaming
15,000rpm. There are no flat-spots, no surges. At 8000rpm, the torque reaches
its plateau and you begin to feel the motor's urgency. Yet the power is meted
out progressively all the way up to the bloodline.
The bike's smoothness is amazing. There are no rough-spots, no
vibes or pulses, no transmission lash (so common with Hondas), no tightness
—just free-flowing endless power. And it's only a 400.1 rode it back-to-back
with a CBR600 which has much more power punched out in fewer rpm. The delivery
seemed frantic and strained compared to the little gull-arm.
On the island, riding around town, the bike pulls easily past
cars from 30mph in sixth gear; you don't even think of changing down. Into the
country, the gradients are no problem to the plucky engine — the torque just
pushes you on to the top with no loss of momentum.
Over the Mountain I was mixing it with anyone, zipping along,
the engine shrieking with glee the more I thrashed it. I could imagine the
comments among the assembled crowd outside the pub at Creg-Ny-Baa, as I
disappeared off down the hill allowing the engine to climb from 6000rpm to over
14,000rpm before the upchange.
"See that? What was it?" "Dunno."
"Just listen! What's he doing to it?!"
Oh for a four-into-one.
It is without doubt the nicest in-line four I've had the
pleasure of yet. Perhaps the best aspect is that despite it 'only' having a
130mph top speed, it's easy and a supremely pleasurable bike to ride. OK, a
Kawasaki KR1 is as fast, but it's near impossible to run one comfortably below
SOOOrpm, and above that it's hysterical.
The contrast between the two couldn't be more stark. I rode the
KRIS to the Island, had both bikes there and did 100 miles of motorway with the
CBR on this side of the water on the way back. It was a joy. At 70mph the engine
was wound up and ready to go at 7000rpm but you could drop below happily
and accelerate right up to its top whack all in the one gear. The CBR delivers
all the enjoyment of a 600 or 750 but without the associated high-rev/high
speed. It's your choice whether to go fast or not.
With so much effort going into the frame design and
construction, it's no surprise that the ride complements the motor. The riding
position feels just like an RC30. Oh you've never ridden one? Well, you're right
over the front, very much in touch with the steering and in attack mode. For me
it felt perfect. The pegs are positioned high and rearset, but not so you can't
use your legs to lift your body to shift weight around. Your bum nestles into
the bump-stop when flat on the tank, doing its job, containing the rider and
giving the feeling that you're working together. Knees slip into and grip the
curves designed into the tank. This I found particularly helpful when being
chucked around the road, riding fast along the bumpy backroads which criss-cross
the Island.
The Isle of Man's rough ride showed up the bike's
only really weak point — the soft suspension. As already pointed
out, the bike is for the Japanese home market and its diminutive punters. Indeed
we all tended to dwarf the bike.
The rear spring on the Showa unit, clearly visible through the
skeletal frame, has four coils. The damper doesn't stand a chance with yer
average flabby Brit on board. For the Island (and everywhere else for that
matter) we screwed it up all the way and wound the compression adjuster all the
way in. It still bottomed out on the big ones and lost much of its travel to the
rider's weight. We let Alex the Art Ed have a go just so we could laugh at his
Sumo-proportions crushing the breath out of it. Poor baby. The logical thing is
to buy an aftermarket shock for it and send the OE back.
Things were a little more hopeful at the front. The fork dampers
are of the cartridge type, adjustable on the fork top for preload with a
stepless screw. They work best about three-quarters way in.
Despite the shortcomings, the suspension is extremely good when
the road isn't too bumpy. They must have nice smooth roads in Japan. No doubt if
the CBR comes to Britain, they'll uprate the springs. Meanwhile, back on the
Island, I could feel the suspension pounding away beneath me, letting the odd
big one get through to shock me in the coccyx. On the smooth parts of the
circuit, the bike could be ridden like a racer — flat-out in long, open bends
without fear of ripples and dips sending the bike into a wobbler.
The steering brings to mind the RC30 quick but stable at
all speeds with racer geometry: 24°30' of rake, 91mm of trail. In slow
bends roundabouts there's a touch of understeer which has you
unconsciously pulling on the left bar slightly to counteract. It's probably a
combination of low profile tyre (120-60/17) and the particularly short trail.
Whatever, it goes when you pick up speed; indeed it comes into its own, being
light and responsive and precise in line. It's a bike you don't have to think
through corners leaving you to concentrate on where you want to go.
Braking while banked over presents no dangers either — unless
you get hold of too much. The front twin discs float and are 296mm in diameter.
Calipers are the excellent twin-piston Nissin tackle and give enough pinch to
haul you down and lock the front wheel with one finger pressure.
The general finish of the CBR was cause for admiration and
compliments. The detail is excellent — the swoopy mirrors, the click-lock flush
filler cap, handlebar-mounted choke, the in-board chain adjusters, Dzus-type
fairing fasteners, dazzling twin headlamps (although dip beam is rather poor),
hand-span adjustable levers, wide, comfy rubber-foam seat, RC-type six spoke
wheels; the pillion footrests fold-away in two planes to tuck out of sight; the
pillion pad flips up to reveal enough space for tools, an oversuit and a jam
butty.
What really made everyone outside Bushy's dribble into their
pints was the bike's looks. We just haven't seen anything like it and nothing as
cute. It's like having a sly glimpse of the Honda drawing board: "Oh, this must
be what we'll get next year." The futuristic design of the aluminium and plastic
together with the colour and graphics put the bike ahead of anything currently
available. It's a stunning little motorbike.
Around the track the CBR400RR drew more stares than Carl
Fogarty; indeed it drew his steely stare too as I was parking up in Douglas the
day after his victories in the Supersport 400 and the Senior TT. "Is it faster
than the NC30, then?" he asked, his piercing blue eyes turning a tinge green —
thinking of next year's TT no doubt. "Dunno, never ridden one. Have you?" I
replied, stupidly.
The Isle of Man was the perfect place for its European debut —
the ideal venue for a thorough test and for a thorough pose. It was the easiest
bike to find again along the busy prom. Just look for the tight knot of leathers
and Belstaffs crowding round, pointing and mumbling incoherently about seabirds,
boomerangs, bananas and Eddie Lawson. Funny lot bikers.
Source Superbike 1990
