honda crf 450 motard                                      

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.