Engine assembly is the main manufacturing activity in HYMM. Motorcycle engines ranging from 105 – 135 cc are assembled at a flexible assembly line which is able to accommodate various model line-ups (moped and scooter) and raise capacity to 160,000 units per year.
Sub-assembly processes are performed in parallel and synchronized with the main assembly processes. Kit-supply system is put into practice in arranging engine components at the warehouse before supplying to the assembly line. The components are assembled at 45 stations and completed engines are delivered to customer by trucks daily.
Steel and aluminum parts such as Crankshaft, Crankcase, Crankcase Cover, Cylinder Head and Cylinder Body are machined at various lines using advanced technology mainly CNC machine tools. Most casting and forging materials for machining are procured locally whereas some are imported from overseas Yamaha (Thailand and Indonesia). Machining is the second major production activity at HYMM.
Painting shop is capable of painting steel, aluminum and plastic parts. After machining, aluminum Crankcase Covers are painted in either black or silver color by a manual batch production method. Plastic parts from local vendors are also painted in the shop. Facilities in the painting shop include a chemical (chromating) treatment line, a spray booth which can occupy three sprayers at a time, and four baking ovens. The facilities can produce almost two thousand parts (engine Cover) per day.