This is the first image of Honda’s Moto3 competitor in “production” trim. Retailing for €26,500 ($38,200), the Honda NSF250R will give teams a turn-key entry to the 125GP-replacing four-stroke class. The highlight technical feature is a reverse cylinder, which locates the intakes at the front and exhaust at the rear to maximize gas flow through the engine. It’s the same size as the outgoing RS125R.
Update: 17 images live from the unveiling in Spain. Man, that thing is tiny.
Where the four-stroke NSF250R can’t match the two-stroke RS125R is, unsurprisingly, weight. The old bike weighed 71kg, this new 250 weighs 84kg or 185lbs. The minimum total weight for bike and rider in Moto3 is 184kg, leaving room for a 220lbs rider or, more likely, a fair amount of ballast.
To centralize that mass, that single cylinder is canted back at a 15-degree angle. It develops 47.6bhp at 13,000rpm and 20.6lb/ft of torque at 10,500rpm. Rules limit maximum revs to 14,000rpm. That compares favorably to the 43.3bhp at 12,200rpm and 18lb/ft at 12,225 of the old 125. That’s right, a four-stroke 250 makes power at higher revs than a two-stroke, 125 GP bike. This class should be pretty exciting after all.
As you’d expect, that engine is pretty high-tech. Titanium valves are claimed to reduce friction as well as weight and the cylinder is offset to decrease frictional losses. You can read more about offset cylinders here. Friction is further reduced by a nickel silicon carbide cylinder coating. The gearbox is a stacked cassette item, reducing engine length and allowing easy ratio swaps.
Honda is also claiming significant aerodynamic gains for both efficiency and cooling.