Engine / Motor / Motorcycle Engine Motorcycle Engine 90cc: Main Parameter for SS90: Engine Specific: single cylinder/four strokes/ignition/horizontal Bore:47.0mm Stroke: 49.5mm Displacement: 90mL Compress Ratio: 8.8:1 Rated Power: 3.8kw/7500±375rpm Max. Power: 4.3kw/8000±400rpm Max. Torque: 6.0N.m/6000±300rpm Idle Speed: 1500±100r/min Chongqing Shuangshi Motor Manufacturing Co.,Ltd Website: http://motors.ec51.com