• Introduction
  • Concept
  • Styling
  • Power Unit 'eSP'
  • Frame/Chassis
  • Technical Specifications

Power Unit 'eSP'

Key features of a new engine

Key low-friction technologies
  • Offset cylinder reduces friction between piston and cylinder.
  • Piston weight has been thoroughly reduced through CAE analysis.
  • A spiny sleeve with minute spines on the outer surface of the cylinder sleeve has been adopted to reduce oil consumption and improve cooling performance.
  • A shell-type needle bearing is used for the rocker arm shaft to reduce friction.
  • Smaller and lighter rollers are used together with an optimized cam profile and valve spring load.
  • Radiator core with high cooling efficiency has been adopted, resulting in a smaller and lighter cooling fan on the back of the radiator and the reduction of friction loss.
  • Oil agitation loss has been reduced through modifications of various sections inside the transmission case and a 36% reduction of transmission oil capacity from the current 125/150cc engines (based on Honda research)
  • Bearings for each of the three axes in the transmission unit are exclusively designed according to the load received, resulting in an optimal set of specifications that lessen the rolling resistance inside the bearings.
Excellent combustion efficiency
  • A compact combustion chamber design incorporates burning velocity and cooling performance suitable for an engine that emphasizes torque characteristics in the practical rpm range of 125/150cc scooters.
  • Air intake port connection to the combustion chamber has been redesigned into a smoother shape that does not impede the flow of the fuel-air mixture.
  • Ignition timing has been optimized by improved knocking resistance created by a highly efficient radiator and a water jacket that efficiently cools the combustion chamber.
Electronically controlled ACG starter
  • High-quality start that is smooth and remarkably quiet has been realized through an electronically controlled ACG starter, which serves as both a self-starter and a dynamo (power generator). An advanced idle stop system has also been realized.
  • Intelligent electronic control improves fuel efficiency through reduced friction during power generation.
  • Swing-back that returns the crank to its position before air intake is electronically controlled for easy restart, and a decompression mechanism mitigates cranking resistance arising from the compression pressure generated by starting the engine
New engine photo
New engine photo
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