Spare Bolts Kit for Athena Cylinder Kit

This complete kit of bolts with specific Allen key was developed by Athena for the Athena cylinder kits for air cooled vertical Yamaha-Minarelli engines and therefore for legendary applications such as MBK Booster / Yamaha BW’s or the iconic Aprilia SR. The OEM head and cylinder tightening based on studs has been eliminated introducing a new system 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. This kit is compatible only with the following Athena cylinder kits:P400485100089: Big Bore Cylinder Kit with Head Ø47,6 mm, Pin 10 mm, Flat Head PistonP400485100090: Big Bore Cylinder Kit with Head Ø47,6 mm, Pin 12 mm, Flat Head Piston