2013/2/1     On January 28, Honda unveiled a new straight two-cylinder water-cooled 400 cc engine. They plan to begin implementing them into new sports bikes beginning this summer, for the domestic market. 

     Yoshiki Nagahashi, head of development for the new engine at the Honda R&D's Motorcycle R&D Center, said, "We approached power characteristics and component configuration with emphasis on precise linear acceleration and deceleration, as well as responsive control in full-body maneuvers like braking and entering and corner exit acceleration." 

     He elaborated, "We discussed what makes and engine cool with the design department from the very start of planning, and developed it with the aim of making an engine that would please the majority of our domestic customers while meeting the demands of the development members." 

     As a result, "We focused on the characteristics of the most frequently used low and moderate RPM ranges to make it easy to handle for an entry-level user, and set the maximum RPM at 9,500. We chose a straight two-cylinder water-cooled engine to match these engine characteristics. In order to improve intake performance up to 9,500 rpm, we researched the optimum valve size, and used a bore stroke of 67 mm by 56.6 mm." 

     Comment: The bore is the same with the new 500 c.c. engine while the stroke is decreased, (56.6 from 66.8 mm). 
 2013/1/29.      The 400cc engine, the company's first new one of that size since 2007, will probably used to extend the CB range. The bike is slated to make its domestic debut this June or July. 

     While Honda previously used mainly Japanese-made components for 400cc engines, the new one will share many parts with a 500cc engine made in Thailand. The firm seeks to lower procurement costs and pass on the savings to consumers in motorcycle prices. 

     The new engine is expected to be assembled at a Kumamoto Prefecture plant in Japan. At least 50% of the new bike's parts will be procured from abroad as well. Of the 220,000 or so Honda motorcycles sold in Japan last year, just 4,300 were 400cc-class products, with their many unique components pushing up costs. 

     However the new engine could be important option in various countries around the globe as the competition at this engine capacity is escalating rapidly. From the dyno-chart image provided it can be derived that the red line will be at 9500 rpm..