Honda NS400R
With Ian Falloon
The father of Honda motorcycles, Soichiro Honda, was an avid fan of four-stroke bikes and long after he retired in 1973, the company remained loyal and committed to four-stroke street bikes.
Finally, after sticking with four-strokes for 32 years, Honda released their first two-stroke street bike, the H100 in 1981. This was a foreshadowing of Honda’s change, coinciding with Honda’s change of heart. matches the 500 cc Grand Prix comeback with the NS500. two-stroke trio in 1982.
The racing NS500 is a great machine and an inspiration for Honda to produce MVX250F. This was released in 1983 to replace Yamaha’s successful 250LC. Unlike the 110° V-three NS500 (with the cylinders arranged one down and two up), MVX250F is 90°V-three, with the two outer cylinders horizontal and the third vertical.
This allows more space under the saddle for the oil tank and battery. To correct any imbalances, the cranks are aligned, with a heavier hub bar and thinner inner flywheel, and 15mm outer flywheel. To the left of the crank is the electronic ignition, with the water pump drive and clutch on the right. The crankshaft runs in four ball bearings and an inductively adjustable reed valve.
The entry gate is also simpler than that of the racers, with four conveyer ports and a single bridged inlet replacing five giant conveyers and intake ports. Despite these impressive specs, the performance of the MVX250F is disappointing and after a year it has evolved into the much superior NS400R.
Produced in just two years, 1985 and 1986, the NS400R is one of Honda’s crown jewels. As it was always intended to be a model primarily intended for the Japanese domestic market, displacement was intentionally kept below 400 cc to reduce registration and insurance costs in Japan. Unfortunately, this has always limited its appeal in export markets, where it struggles with the 500 cc Suzuki RG500 and the full-fledged Yamaha RD500.
According to the layout of the MVX250, the trio of 57 x 50.6 mm has a capacity of 387 cc. Unlike the MVX250 (but as on the racing NS500), two ATAC (Automatic Controlled Torque Chamber) exhaust systems are installed on the front cylinders.
The ATAC is designed to boost low- and mid-range power by varying the exhaust system volume in rpm. The carburetor is three 36 mm Keihin, and with a compression ratio of 6.7:1, power is 72 hp at 9500 rpm. A six-speed transmission is needed to keep the top-notch engine alive.
In typical Honda style, the NS400R is beautifully designed with Rothmans white detailing, modeled after Spencer’s Grand Prix machines. Adorned with dozens of beautiful alloy castings, including the frame and swingarm, the wheels are 16- and 17-inch tangential-spoke racing-style wheels. Unlike the MVX250 with its unusual accompanying disc, the braking system is a regular 256 mm disc, with dual piston calipers.
37mm pneumatic fork with TRAC (Torque Reaction Anti-Dive Control) and rear suspension with adjustable hydraulic rear shock. At 163 kg, handling is excellent and the NS400R is surprisingly fast, with a top speed of around 215 km/h.
Unfortunately, the top-notch engine made the NS400R difficult to live with and it had to compete with the larger Suzuki RG500 and Yamaha RD500LC. Despite its superb execution, the NS400 was lost in no man’s land, between the 500s and 350s, and is now a rare monster.
Five facts about two-stroke Honda racing cars
- Freddie Spencer brought Honda its first 500 cc Grand Prix title in 1983, riding a three-cylinder NS500.
- Facing more opposition from Yamaha, the four-cylinder NSR500 replaced the trio in 1984. Spencer did this to win the race. 1985 500cc World Championshipalso won the 250 cc title that year.
- After Spencer unexpectedly retired from the 1986 Grand Prix, Wayne Gardner took over as the lead driver on the Rothmans Honda team, comfortably winning the race. 1987 500cc World Championship.
- Gardner received a new NSR500 in 1988 but the type was not developed and Gardner found it very difficult to drive. Afterward 1989 Lawson switched to Honda from Yamahawon the title after Gardner broke his leg earlier in the season.
- The last era of dominance of the NSR500 was that of Mick Doohan. After overcoming a serious injury in 1992, Doohan won five consecutive titles between 1994 and 1998.
