The Honda NX250 is a crossover

dual-sport motorcycle A dual-sport motorcycle is a type of street-legal motorcycle that is designed for both on and off-road use. The terms ''all-road,'' ''on/off road,'' and ''dual-purpose'' are also used for this class of motorcycles. Dual-sports are equipped with ...

produced by Honda, available in the United States from 1988 through 1990. It is a lightweight bike intended for both on-road and off-road riding. The NX250 featured the new MD21E engine which is a liquid-cooled, 249 cc, single-cylinder, four-valve,

DOHC An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion c ...

four-stroke A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directio ...

with an electric start. It has a bore and stroke of , 11 to 1

compression ratio The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values. A fundamental specification for such engines, it is measured two ways: the stati ...

, and a six-speed transmission. The suspension has forks with 8.7 inches travel up front, and Pro-Link with 7.9" in the rear. The NX250 has a wheelbase and a dry weight of . The seat height is . In some countries Honda continued production of the NX250 up to 1993, where it was named Honda NX250 Dominator.

AX-1

The Honda AX-1 is a modified version of Honda NX250 intended only for the Japanese market but was offered in

Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...

. Using the same chassis as the NX250, the AX-1 came standard with alloy rims, aluminum Pro-Link rear suspension this time with a rear disc brake, dual round headlights, taller cams, stainless steel exhaust and different carburetor settings. The valve clearance check interval is every . Spares commonality with NX250 is high, but certain parts are rare, such as the rear luggage rack, exhaust heat shield, cylinder heads and valve guides and headlights. However, the MD21E engine is known to run to over 100,000km without major overhaul. Part of this is due to an extremely durable Nikasil-coated cylinder bore. Nikasil is a chemically deposited layer of silicon carbide, which is typically twice as hard (on the

Mohs scale The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

) as iron/steel liners. The rear cush drive rubbers are not available and owners have made their own by modifying Honda Civic suspension bushes of similar dimensions, although they rarely fail during the life of the vehicle. There is a small but dedicated online community for the NX250 and AX-1. With the rise of popularity of adventure bikes, there is renewed interest in the Honda AX-1 primarily for its light weight and power exceeding modern contemporaries such as the Honda CRF250L.

References

NX series Dual-sport motorcycles Motorcycles introduced in 1988 {{motorcycle-stub