Standard Bore Cylinder Kit Ø 56 mm, 250 cc

Born at the end of 1994 to celebrate Aprilia's victories in the 250cc class of the MotoGP, the Aprilia RS 250 is a true milestone in the history of two-stroke sports bikes. It all began in 1987 when an Aprilia ridden by Loris Reggiani won the San Marino Grand Prix and culminated in absolute domination between 1994-1996 when Max Biaggi secured three consecutive World titles. Today, this full-fledged Race-replica, capable of producing in excess of 280 HP/liter, remains the most powerful road-going 250 cc 2-stroke motorcycle ever produced! The long experience acquired in the world of Racing allowed the Athena R&D Department to create a solution that filled a market gap: a Standard Bore cylinder replacement kit for the original Aprilia-Suzuki, which can be installed without any modifications, is fully compliant with the original specifications and comes with all the required components. Athena's Engineering and Design Department manages the entire development and approval process of the cylinder kits. The team designs the kit elements together, and then the quality control technicians test them and validate the parts before they are used directly by drivers. The result is a combination of engine components that ensure optimal synergy between the parts in accordance with our high standards of maximum performance, reliability and durability. THE CYLINDERThe cylinder is made of a high-silicon-content aluminum alloy machined using innovative technology and state-of-the-art Computer Numerical Control (CNC) machine tools to ensure tight manufacturing tolerances and maximum precision.The cylinder is ready to be installed with no changes to the engine crankcase required, and includes the oil tank mixer fitting and the brass bushing for the exhaust valve shaft, all preassembled. The latter features a threaded valve seat instead of the classic pressed-fit type, making any future disassembly and reassembly operations much simpler.The Athena technicians also redesigned the coolant hose as the original sleeve installed on the Aprilia-Suzuki cylinders is susceptible to corrosion. They created a separate brass sleeve that can be screwed directly into the cylinder, thereby simplifying the maintenance of this component that is essential for the proper functioning of the engine.The seats of the head studs have also been redesigned and, unlike the original, they are no longer in communication with the water passages of the cylinder to guarantee optimal contact pressure and maximum sealing in all conditions.The inside of the cylinder wall is coated with Motor-Niksil to ensure smoother sliding of the piston, less friction, and reduced wear of the piston rings, for durable and consistent performance. The Motor-Niksil treatment provides extra hardness and superior strength inside the cylinder, limits wear and helps maintain the nominal bore size over time.In addition, the inner diameter of the CNC-machined exhaust crossbar eliminates the risk of excessive expansion that could damage the piston, guaranteeing optimal reliability and durability over time. PISTON KITThe Athena flat-head piston kit was designed and developed specifically to maximize the high-performance of this cylinder kit. We selected a high-silicon-content aluminum alloy to ensure a low coefficient of thermal expansion, and consequently, much tighter mating tolerances between piston and cylinder.The piston skirt is lighter for maximum performance and the surface has been coated with Molybdenum Disulfide to reduce friction, lessen noise, and improve sliding of the pistons.To ensure constant and effective lubrication of the needle roller cage bearing and the connecting rod small end shims (spacers) in all conditions, Athena technicians have designed a window, produced with CNC cutting-edge machining tools, on the intake side of the piston skirt; on the exhaust side, the skirt features holes for the lubrication of the exhaust crossbar.The included piston rings are made in Japan from a special steel and feature a chromium nitride coating applied using a PVD process, ensuring low friction, smoother sliding of the pistons, and a longer lifespan.The piston pin is biconical for greater strength and lightness and is made of a nitride-treated aeronautical steel alloy to guarantee maximum hardness and minimal friction. GASKET KITThe gasket kit, developed by Athena technicians, includes all the gaskets necessary for installing the cylinder kit and is fully compatible with the original Aprilia-Suzuki components.The materials and manufacturing technology used to produce these gaskets make them particularly resistant to oils, fuels, and mixtures of water and antifreeze or corrosion inhibitors. In addition, they exhibit a superior resistance to mechanical and thermal stress and conform well to sealing surfaces. In particular, the head gasket and the cylinder base gasket were specifically redesigned using an innovative reinforced graphite material to ensure excellent adaptability to surfaces and optimal and uniform sealing over the entire area. To further improve the sealing ability, a special silicone bead sealant is applied using high-precision screen printing machines.The gaskets also undergo a surface finishing treatment to prevent adhesion to the cylinder head or engine block surface, which would cause the gasket to rip and deteriorate over time and lose its uniform sealing ability.