Big Bore Cylinder Kit with Head Ø 47,6 mm, Pin 12 mm, Flat Head Piston

Athena is pleased to announce an absolute novelty in the world of air cooled vertical Yamaha-Minarelli engines and therefore for legendary applications such as MBK Booster / Yamaha BW’s or the iconic Aprilia SR*.With this brand new big bore cylinder kit, Athena R&D department brings on this cylinder technical solutions usually applied only on high performance engines, such as on the 2T Racing GPs. The multiple innovative technical solutions introduced in this project allow to reach performances never achieved before with this engine. With this new cylinder kit Athena is introducing many solutions never seen before on these applications. The result is just the best performing cylinder kit ever designed in its category. A REVOLUTION ON THE PORTSAthena’s technicians wide experience in the 2T sector allowed them to approach this cylinder challenging the traditional design. The intake and exhaust ports have been totally redesigned: analyzing the thermo-fluid dynamics of the engine, overall performances have been highly improved in terms of power and torque, achieving new levels for the first time ever. The intake port is reinvented, adding a CNC machined fifth port to grant a higher gas flow incoming in the combustion chamber. Using the innovative fixing system directly on the crankcase without using stud bolts, Athena developed an exhaust outlet with a bigger oval shape and side auxiliary ports. This solution has been applied for the first time ever on this kind of cylinders. REINVENTED PATENTED FIXING SYSTEMThe regular head and cylinder tightening based on studs has been eliminated introducing a new system of special bolts pretty close to the ones used in the high-level performing engines. Tightening the cylinder to the crankcase (Racing type) with these bolts and a special Allen key leads to a reduction of the thermal expansion of the cylinder, bringing a more efficient tightening and on the other hand allows the sophisticated redesign of the exhaust port that makes this product so special and unique. NEW RACING PISTONThe flat head piston has been developed focusing in particular on the interaction with the intake. The CNC machined opening on the piston skirt is designed to maximize the inlet flow, to allow greater pressure on the pump casing and better lubrication of the needle bearing.