Honda Motor unveiled its all-new 2018 CRF250R, the company’s leading mass-produced motocross bike. The highly anticipated motocross model features a host of updates, including more aluminum in its frame and titanium in the fuel tank and engine. As a result of the engine and chassis updates, the 2018 CRF250R enjoys a 3% improvement in start performance compared to its predecessor, along with improved acceleration and handling.
Aluminum Chassis
The 2018 CRF250R follows achieved a highly concentrated mass and a very low center of gravity, with weight reduced overall but particularly up high and at the ends of the vehicle. The new CRF is built around a new-generation aluminum twin-spar frame, with a slim and low layout and minimal front-end lift–ideal for strong starting and acceleration. The main spars of the aluminum frame are now tapered to optimize flex characteristics and provide good stability and reliable rider feedback, while a shorter wheelbase improves overall agility. An extruded subframe end saves precious weight up high in the vehicle.
Titanium Fuel Tank and Engine
The all-new titanium fuel tank contributes to weight savings and the low center of gravity. Nippon Steel & Sumitomo Metal Corporation (NSSMC) supplied the titanium sheet for the new fuel tank, which was developed for the previous CRF450R bike model — the first time in the world that titanium was adopted for the fuel tank of mass-produced bikes. NSSMC worked with Honda to develop a technological proposal for processing titanium sheets to match the special requirements of fuel tank manufacturing, such as for press formability, weldability, and anisotropy. NSSMC’s pure titanium (JIS 1), TP270C was approved for adoption for the fuel tank. Leveraging on the features of titanium (lightweight, strength, and high corrosion resistantance) for the fuel tank has contributed to reducing its weight by 18 ounces. The fuel tank is a critical place to loose weight because of how high it sits on the bike.
Honda engineers achieved increased power (particularly at higher revs) by giving the 249cc engine an all-new dual-overhead-cam design. The engine features titanium intake and exhaust valves, which are larger and have a higher lift and narrower angle, which provides more room for a new downdraft intake for maximum efficiency. This, in addition to other copious changes, results an engine with more power across the rev range, especially impressive at peak rpm.