Aiming at attainment of the model's development concept
(1)Affordable price, (2)Lowest fuel consumption in its class, (3)Utility/comfort,
development requirements for the power unit of SH125i/150i were set as follows:
To meet these requirements, the new model realized a centralized mass along with a much simpler layout for the cooling system by building the currently front-mounted radiator into the engine. In addition, adoption of an electronically controlled ACG starter, which not only serves as a self-starter motor but also generates electricity, enabled the conventional self-starter motor and gears related to the starting system to be eliminated, making the system lightweight and compact. Furthermore, the functions of various sections other than starting and cooling systems were consolidated, reducing the number of main parts by about 22%.
This liquid-cooled 4-stroke single-cylinder engine for the next-generation 125/150cc scooters incorporates an electronically controlled ACG starter that delivers a quiet start and an advanced idle stop function, and brings with it an approximate 25% boost in fuel efficiency from the previous model (measurement by Honda) by reducing the friction of various parts of the engine as much as possible.
For the fuel supply system, which must accommodate an environmentally-responsive global standard engine that looks ahead to the next generation, PGM-FI (Programmed Fuel Injection system) is incorporated for its computer control that constantly optimizes combustion under a wide range of riding conditions, thus meeting Euro III standards while delivering a powerful ride.
This power unit can accommodate diverse usage environments and always deliver easy-to-handle output and low fuel consumption.