Why I need to use special 4T oil for my 4 Stroke Motor Cycle Engines?

Two Wheeler / 3 Wheeler engines are air-cooled engines unlike the passenger car engines which are cooled by water or by a coolant. The Engines are effectively cooled by the air drag across the engines while the vehicle is in motion. The Engine operating temperatures exponentially shoots up when the vehicle speeds are reduced or the vehicle is stopped since the air drag drastically reduces under these conditions as encountered in a typical city operating conditions. Secondly these vehicles use wet clutch mechanism and the same engine oil lubricates the engine, the wet clutch and the gears. So oil with high Friction Modifier used in Engine Oil will lead to clutch slippage. The Oil used for Four Stroke engines, Two Wheeler / Three Wheeler, need to take care of the higher temperature operating condition as well as it should have controlled friction characteristics to take care of the wet clutch requirement. At the same time it should have reduced friction characteristics as required by ...