Honda CBR 400RR

t'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