MOTORCYCLING WEEKLY, APRIL 23 1985
The NS400R is one of the most eagerly awaited bikes from Japan for many years. KEN FRANKEL rode it at Suzuka
SOFTLY SPENCER
WE have been waiting for a year and a half for the NS400R, the bike that went into the tea-warehouse of Hamamatsu as the MVX400 long ago . . . when colour brochures were torn-up and thrown away and customer's deposits returned and orders cancelled.
Honda felt that it was not yet time to launch their newest street rocket: a three-cylinder, two-stroke in a 90 degree vee-layout that appeared briefly as the MVX250 over here, liquid cooled and with piston-reed valves.
Now it is time, the NS400R is born; a Grand Prix technology baby that walks and talks in imitation of its father, Freddie Spencer. There is even a Rothman's Honda colour replica in limited supply; a special edition with matching touring suit, helmet, gloves and boots.
Here in Japan we were able to ride production models early in April, and the total riding impressions from the Japanese motorcycle press were unanimous: this is a mild-mannered machine for just about anybody. It's not too fast and it's not too dangerous. It could be a perfect two-stroke beginner's bike for the rider who wants two-stroke performance with four-stroke manners. Plenty of low-down pulling power that makes it unnecessary to lift the revs and slip the clutch to start that forward progress from stoplight to stoplight. In fact, despite its racer looks and ergonomics guaranteed to give you permanent racer-slouch, this is a better city bike than a race bike. If you want to go production bike racing, we suggest you look for the NS500R which will soon follow.
Naturally, comparisons have to be made. Suzuki's RG-400 Gamma is an impressive 100 per cent racer with no technical compromises made in performance. It is pure Yokouchi . . . the genius behind the new world of Suzuki motorcycles. The Honda NS400R is the combination of many talented individuals and technological input for the street. It is a "user-sensitive" bike, and it's a bike the user will like . . . very much. The two bikes are like comparing varieties of apples, very different in taste and, perhaps, in the way they should be used.
We found the NS400R to be soft-soft; soft in front, soft in the rear. Oh, it was great for just putting around, but at speed there is an understeer characteristic that can be somewhat corrected by adding a little air up front, dialing up the anti-dive, and turning up the rear pre-load.
There is still some understeer when cornering hard but needs confidence to lay it over and power through. If you go off-throttle midway through the corner you'll run wide, as one did at the entrance to the first corner at Suzuka Circuit on our test day.
Our feeling was that the bike was good for a beginner, excellent for an expert, but kind of scary for the rider who is over his head before he knows it. The combination of 63 degrees castor and 100mm trail give the NS400R good cornering characteristics at an easy pace, but give your right-wrist its full exercise and you'll soon be into an area of twilight-zone space warps and strange handling.
Go off-throttle and your apex line shifts to the outside. It takes experience, or supreme confidence, but when carving through the esses at Suzuka circuit we found that you can keep the power on, lay it over, and cut a clean, sharp line.
The powerful 387cc engine revs easily, and while it will over-rev past the 10,500 red-line on its way to 11,000 and a once-reached 12,000, the six-gear transmission makes for easy and smooth transitions if you decide to knock it down a gear at the entrance to your favourite corner.
The torque of the engine gives a good pull starting from 7,500rpm, so the power band is wide and serviceable in a multitude of straight/curve/corner applications. The only mis-shifts we experienced were in downshifts from fourth to third.
Braking was excellent both front and back. Up front, the twin discs with dual piston calipers had a good feel, rider feedback and precise control. In the rear, the single disc was very controllable and never produced a rear hopping sensation.
Except for the sitting position, which is more compact than anything Honda has done before (pegs 10mm farther forward than the NS250 and separate handlebars 15mm higher), the NS400R could be a good touring bike.
Oil is always a problem with two-stroke touring but with this bike's two-litre holding tank and good oil control evidenced by no blue-smoke or drippy residue from the exhaust pipes at the end of the day, Honda may have that problem solved. They do make a point of stressing the use of Honda Ultra S oil and careful service to prevent big-end burnishing and small-end seizing.
We rode hard all day, 25 minutes at a time, and then on with the next riders. The engine were stopped each time and starting was a simple and smooth kick with the engine catching on the first one. The tyres were Of Yokohama Getter brand of good street grip and reason road economy. In Japan, this is one of the most pop replacement tyres. While speedometer only goes upkm/h, continuing that calibration would have had our needle resting on the 210-km/h line.
On the negative side, in the parking lot or at slow speed through traffic, your right-hand gets caught between the throttle and the fairing in sharp left-hand turns. Those good mirror positions are also obstacles to winding your way through traffic.
Visually, the NS400R looks just like the NS250, but with an extra aluminium-covered exhaust pipe silencer on the lower right-side. Actually the whole bike is slightly wider. There is no denying that the bike looks fast and racy, especially in its Rothman's Honda colour styling.
Honda is using a computer-assisted frame design which is all aluminium, using multi-ribbed box and cast members.
The seat and rear cowl pieces are supported by an almost straight rectangular set of pipes originating from the lower steering head and cross-braced on top of the engine with lower struts above the top of the single Pro-Link shock and angling down from the rear to join the swing-arm pivot.
The engine is rubber mounted at two points along the lower double-cradle frame and at the rear. Technically, the Vee-three produces vibrations similar to a 125cc single. Honda tried using a balancer shaft but discovered other negative aspects and decided to fully rubber-mount the engine. I found the vibrations to be minor and of little concern in such a smooth and gutsy bike.
The liquid-cooled engine is slim, light and compact, using a single common crank for all three pistons to cut down on power loss. The front two cylinders are fitted with Honda's electronic control ATAC system (Automatic Torque Amplification Chamber), dual exhaust sub-chambers which are open at low rpm and then electronically controlled by a solenoid linkage to butterfly valves which close the sub-chambers at high rpm, producing faster and strong response from the engine in low rpm conditions.
Honda's progressive damping suspension, Pro-Link, is used at the rear with an easy to adjust hydraulic oil pre-load system that uses a dial on the rightside of the bike. Up front, the TRAC system of suspension is air assisted for pre-load adjustments and includes the brake-torque reaction system that controls anti-dive in the front forks. The front tyre is 16-inches and the rear, 17-inches. The Com-Star wheels are all aluminium with flat plate-spokes in black for the NS500 racer-replica look. The drilled triple disc brakes use dual piston trailing calipers and semi-metal brake pads.
The bike is an example of progressive aerodynamic technology from the race course and uses a partially enclosed front fender and full upper and lower cowling. As on the NS250, even the side-stand has a fairing cover.
We have waited for the 400 ... now begins our wait for the 500!
The inside story
HONDA is keen to promote the NS400R as a direct offshoot from the NS500 road racing technology, but its lineage goes back to the time when the three-cylinder racers first appeared on the tracks in Freddie Spencer's hands in 1982.
Honda's first attempt at a two stroke triple was the ill-fated MVX250F. But it didn't use a complete copy of the 497cc racing engine which had the middle cylinder of its engine pointing forward and two cylinders pointing upwards.
In order to fit the three exhaust pipes in with the requirements of the road machine, which needed room for the battery, two cylinders jutted forward and the other up.
The three carburettors pointed forward, feeding the cylinders through reed valves. It looked neat and compact but the novelty was inside. To balance the weight of the vertical piston and rod assembly weighing the same as both the horizontal ones.
But piston failures dogged the motor and the 250 was withdrawn before being launched and the 400cc version shelved.
The NS500R is a redesign of that motor with three equal pistons and a new type of cylinder coating that allows tighter bore-to-piston clearances, plus the addition of ATAC exhaust chambers for broadening the power band.
Capacity is 387cc from the three 57 x 50.6mm pots and in UK spec delivers 72bhp at 9,500rpm (the Japan model is limited to 59bhp).
Size for size, that's more than Yamaha's RD500LC, the NS400R having 187bhp/litre and the Yamaha 176bhp/litre.
The bike's geared for 139mph at 10,000rpm, which with kerb weight of just over 400 pounds should be attainable in good conditions.
The bike that everyone is waiting for is the 500cc version however. With the bore and stroke upped to the 62.5 x 54mm of the racer, power of over 90bhp and a 150mph top speed should be easy without sacrificing flexibility.
more reading:
NS400R press release
MVX400F, the model that never was
NS250R press release
MVX250 features
