Honda CRF series
The CRF line was launched in 2002 as a successor to the Honda XR series. The full sized motocross bikes are equipped with liquid-cooled, single-cylinder four-stroke engines that are available from 149 cc to 449 cc. They now have dual-sport motorcycles. The more trail friendly CRF's have simple air-cooled engines, and are available from 50 cc to 230 cc. The Honda CRF450R was the first in the series, followed with the CRF250R in 2004. Further down the line, the CRF450X and CRF250X bikes emerged, both designed for mostly off-road use. They are considered among the best motocrossers of their class, and have been a leading seller since their introduction. The Honda CRF450R has been CycleWorlds Best Motocrosser for a record eight consecutive years from 2001-2009 in CycleWorlds 10 Best Category
|This section does not cite any references or sources. (December 2009)|
Honda employs advanced four-stroke engine technology in their 250cc and 450cc bikes. The engines in these bikes use technology developed in Formula One racing engines. Honda uses an over-square engine design, this means that the diameter of the cylinder is larger than the stroke of the piston. This allows for higher engine speeds and a reduction of reciprocating mass. Another technology that is used is short piston skirts. The "skirt" area of the piston is the portion on the side of the piston which comes into contact with the cylinder wall and aids piston stability. While the introduction of the shorter skirt on the piston helps to reduce reciprocating mass, it also leads to more "rocking" of the piston, or minute unwanted rotation of the piston around the axis of its wrist pin. This leads to more frequent maintenance intervals for the pistons, piston rings, and cylinder walls.
Overall the new high-performance four-stroke engines in Honda's motocross bikes produce much more power per pound than older generation engines and rev more freely; in the quest for more power, longevity is reduced and maintenance is increased.
As of 2007, the CRF X series includes the 250X and the 450X. These bikes are electric start and are still considered race bikes, albeit for off-road rather than motocross. Differences from the R models include lighting, electric start, suspension settings, engine tuning and exhaust tuning for more torque, larger fuel tanks and wider-spread gear ratios.
As of 2008, the CRF L series includes the 230L. Being a dual-sport motorbike, it is factory street legal, but still has a dirt-oriented design. It has a completely different frame and engine from Honda's CRF230F, and most other components are not shared with the (non-street-legal) F-series motorcycles. Both 230s have electric starts. Outside of the United States the CRF230L is marketed as the XR230L.
In April 2013, exactly one year after the initial launch of the CRF250L, Honda announced plans to sell a supermoto version of their dual-purpose motorcycle in Europe. The CRF250M is based on the popular dual-purpose CRF250L, with revised suspension, uprated front brake and 17-inch wheels with wider road tyres, the CRF250M adds another A2 licence-friendly machine to Honda’s line-up.
- Dougherty, Brad, "First Ride: 2004 Honda CRF 450R", Dirt Rider, archived from the original on 2007-03-11
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