Cylinder 4 STROKE Material: primary aluminium alloy with a high content of hardened and tempered silicon, cylinder liner with silicon carbide coating in a galvanic nickel die and crossed smoothing with two diamond passages with very limited tolerances. Machining: on machine tools with high precision numerical control. Cylinder-piston connection with an allowance of 0.05 mm. Recalculated and upgraded heat exchange surfaces. Piston Ultra compact with 3 rings. Material: special aluminium alloy with high silicon content, low thermal expansion and a tin facing on the sliding surfaces. Machining on machine tools with numerical control. Lightened and reinforced. Upgraded heat exchange surfaces. Piston rings Special rings with high sliding ease and very high mechanical resistance. I° ring compression in nitrided and chromium steel. II° special cast iron ring. Three - piece scraper ring made of chromiumplated specialsteel alloy.