The new 70cc Athena cylinder kit for Yamaha-Minarelli Vertical Engines (CW)

Entirely reinvented fastening system.
The normal cylinder head and cylinder clamping, based on studs, has been eliminated to introduce a new system with special bolts, adopted in racing applications. This solution reduces cylinder expansion, thereby ensuring more efficient clamping, and allows for a sophisticated redesign of the exhaust port.

Redesigned intake and exhaust ports.
The intake features a CNC-machined fifth port that ensures a greater flow of fresh intake gases, while the oversized exhaust port has an oval geometry with side boosters. This last solution cannot be found on any other cylinder of this type on the market today. The result is the highest performance cylinder kit of its
kind ever conceived.

Special, flat-head piston.
Development of the piston was conducted focusing on the interaction with the intake. The CNC-machined window on the casing is designed to maximise the intake flow, thereby favouring greater pressure on the pump casing and better lubrication of the roller cage.