American Honda announced to its dealers today that it is bringing in the CBR250R, a bike that was developed with the aim of a “global model” that could be sold in multiple markets across the world. Built in Thailand, the CBR250R has the potential for mass appeal (i.e., cheap and easy transportation) as well as the ability to pass under the usual restrictions that prevent larger displacement bikes from importation to various countries. It also fills a hole in American Honda’s lineup that has existed for quite some time—a learner bike that is more sport-oriented instead of the obvious cruiser lines of its long-running Rebel 250.
The all-new liquid-cooled, 249cc single-cylinder engine powering the new mini-CBR sports some interesting innovations for an econo-based model. Its bore/stroke dimensions of 76 x 55mm are fairly conventional, as is its four-valve head pumping a compression ratio of 10.7:1. In a first for the motorcycle world however, the double overhead camshafts actuate the valves via rocker arms equipped with a roller bearing at its contact point with the cam lobes. The design not only reduces reciprocating weight, but also mechanical friction losses. Another interesting innovation is what Honda calls the “spiny sleeve”. In an effort to improve cylinder wall cooling and reduce distortion (thereby reducing blowby and oil consumption), the cylinder sleeve’s outer surface (opposite the piston side) is covered with thousands of tiny “spines”; this gives more coolant contact area for heat transfer without drastically affecting coolant flow.
The crankshaft also features a unique hybrid roller bearing/plain bearing design. In a first for a Honda single-cylinder engine, the crankshaft’s main bearings utilize plain bearing inserts instead of the usual roller bearings. Also, instead of the more common aluminum-alloy-based bearing material, the CBR engine’s plain bearings are cast iron, which not only eases manufacturing, but also improves the rigidity of the crankcase housing, as well as reducing changes in the crank journals’ oil clearances due to thermal expansion. The assembly of the crankshaft allows use of low-friction roller bearings for the rod journals. A primary counterbalancer shaft driven off the clutch primary gear is used to augment the crank’s counterweights, allowing the crankshaft’s built-up design.
The PGM-FI’s throttle body has a single 38mm diameter throttle plate, with a six-speed transmission down below transferring power to the 140-size/17-inch rear tire. Braking is handled by a single 296mm disc clamped by a two-piston/slide-pin caliper, with a single 220mm/single-piston caliper combination out back; an ABS version of the CBR will also be offered. Befitting its beginner budget aspirations, the 37mm conventional fork is non-adjustable, while the single Pro-Link rear shock setup is adjustable only for spring preload, and in only five positions. Styling cues are obviously lifted from the VFR1200F. Available colors will be Metallic Black and Red/Silver, and deliveries are expected in Spring 2011.
Even though the CBR250R is touted as “an affordable entry into the sport of motorcycling”, there was no MSRP listed along with the press information, so it remains to be seen how it will compare with the current king of the 250s, Kawasaki’s long-running Ninja 250R.
American Honda's press release follows:
Torrance, CA: American Honda Motor Company’s Powersports Division announced to its dealers today the release of an all-new motorcycle designed for those entering the sport of motorcycling, one that’s sporty, fun, lightweight and affordable: the CBR250R.
“This is really an amazing machine we’re adding to Honda’s list of models for 2011,” said Powersports Press Manager Bill Savino. “The CBR250R is specifically aimed at new riders, yet it’s packed full of high-tech features and offers great performance, all in a lightweight, affordable package. This new model expands another segment of the market for Honda buyers.”
More detailed information and images of Honda’s model line can be found on powersports.honda.com or see your local Honda powersports dealer.