Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/778560
40 to 120 degrees F, the manufacturer's suggestion was an SAE 20W40. In addition, the selected oil had to meet the American Petroleum Institute's service designation of SG or higher as well as the MA standard by the Japanese Automotive Standards Organi- zation (JASO). Other key findings in my user's manual included information about not using diesel-specific oil with an American Petro- leum Institute (API) classification of CD or higher. In bold letters, it stated, "Do not use oils labeled Energy Conserving II or higher." The main reasons for this statement were because of my motorcycle's wet clutch and the friction modifiers that energy-conserving oils use, as they can lead to premature clutch wear due to clutch slippage. Understanding Viscosity Viscosity is defined by the oil's resistance to flow and shear. The higher the viscosity, the more viscous the fluid. The lower the viscosity, the easier the fluid flows. With motorcycle oils, the viscosity grade is repre- sented by the SAE grading system. The higher the grade, the more viscous the oil. Temperature has a significant impact on an oil's viscosity. Take honey, for example. At cold temperatures, honey flows very slowly, meaning it has a high viscosity. If you apply a heat source, the honey will flow easier, changing its viscosity. With a higher viscosity, oil has increased load-carrying capabilities. It is essential to understand viscosity when selecting a motorcycle oil. Viscosity is an oil's most important physical property. The viscosity is what keeps the internal surfaces of your engine from coming into contact with each other. If the viscosity is too low, the gears inside the gearbox will come into contact and produce friction, leading to higher oil temperatures, decreased gear protection and increased wear. If the viscosity is too high, it may take longer for the oil to reach the cylinder walls, resulting in wear. Selecting the right viscosity requires a balance between the seasons, regional temperatures and the type of driving the rider will be doing. Decoding the SAE Grading System Rarely are monograde lubricants used for motorcycle applications. A monograde oil is represented by a single designation, such as SAE 40. These oils have a much narrower operating temperature range than that of multigrade oils. It's best to choose a viscosity range based on where and how you ride.