Athena Cylinder Kit Ø85mm Big Bore 290cc till CRF25R 18-

THE CYLINDER

The cylinder with extreme Ø 85mm oversized bore is made of aluminum alloy and high silicon content.

To allow such an increase in bore while maintaining the original block, the Athena technicians decided to use a steel cylinder liner.

This cylinder liner is not inserted inside the cylinder bore with pressure, but instead, it is positioned directly in the mold through an innovative co-fusion production process. This method, studied and tested internally, makes it possible for the aluminum casting to "embrace" the steel, making it integral with the aluminum. This allows excellent heat transmission and an efficient mechanical grip that prevents reciprocal sliding, even after many hours of use, guaranteeing perfect union and reliability over time.

The inside of the cylinder liner is finished with a galvanic nickel-silicon coating treatment developed by Athena and subsequent polishing, to obtain maximum smoothness and optimal resistance to wear.

The winning feature of this new Athena project is to have developed a cylinder resulting from the union of two different materials, with particular attention to the design of the cylinder liner. The superior geometry of the cylinder liner was designed to ensure maximum sealing in the combustion chamber and to guarantee the right contact pressure between the components, under all conditions, avoiding pressure losses and leakage of liquids and/or gases.

PISTON KIT

The forged aluminum alloy piston is a guarantee of resistance and lightness. Furthermore, machining with latest generation CNC machines ensures perfect geometries and reduced tolerances.

The undercrown design has a fully open boxed bridged design to combine greater resistance to fatigue, lightness and better cooling of the piston crown.

The piston crown was engineered with particular care to optimize it for greater resistance, better heat dispersion and an optimization of the compression ratio to ensure greater driving elasticity and reliability over time.

The shell incorporates a molybdenum disulfide coating, which is applied by screen printing to reduce friction and noise, and improve sliding. The segments included are made in Japan out of special steel, with a chromium nitride coating applied with the PVD process, guaranteeing low friction, better smoothness, and a longer lifespan.

The gudgeon pin, specifically designed for this type of extreme application, is biconical and made of aeronautical steel alloy with a nitriding treatment with DLC "Diamond-like carbon" surface coating, which guarantees high hardness and low friction.

GASKET KIT

The set of gaskets included in the kit, developed by Athena technicians, were specifically designed for our new aluminum cylinder with steel liner, to ensure maximum seal and durability. 

The head gasket is an MLS (Multi-layer Steel) type, designed specifically to withstand increasingly higher pressures and temperatures. It was made using the latest generation laser cutting technology.

The material used is stainless steel with high elastic return, for high adaptability to the surfaces, and to guarantee an excellent, uniform seal on the whole surface. To further improve the seal capacity, it is equipped with specific raised points around the cylinder liner and the oil and water passages.

To maintain the synergy ensured by our internal design process, the cylinder base gasket is also made by laser cutting in stainless steel with a specific rubber coating.

The rubberized inserts and the raised relief around the cylinder liner are the Athena team's design response to effectively and constantly support the cylinder body subject to the closing load of the cylinder head stud bolts.