In order to achieve their powerplant development goal of increased power (particularly at higher revs), engineers gave the 249cc engine an all-new dual-overhead-cam design, using a finger rocker arm with Diamond Like Coating (DLC). The titanium intake and exhaust valves are larger and have a higher lift and narrower angle, while the valve springs‰Ûª coils now have an oval cross-section to keep engine height as low as possible.
The engine has more oversquare dimensions, the cylinder offset has been increased, and the piston now features a bridge-box design‰ÛÒa first for a production Honda motocrosser. The intake system is now of a downdraft design for maximum efficiency, there are twin exhaust ports, and the dual exhaust features smoother routing and optimized pipe length. An electric starter is standard, powered by a small, lightweight lithium-iron phosphate battery. The end result of the copious changes is an engine with more power across the rev range, especially impressive at peak rpm.High-performance, 249cc single-cylinder engine with dual-overhead-cam design and higher rev limit.