ASTM D4857 Standard Test Method for Determination of the Ability of Lubricants to Minimize Ring Sticking and Piston Deposits in Two-Stroke-Cycle Gasoline Engines Other Than Outboards
4. Summary of Test Method
4.1 The test is run in a 347 cm3 Yamaha RD-350B twin-cylinder air-cooled motorcycle engine. It is intended primarily to evaluate ring sticking and piston skirt deposits. Spark plug fouling, combustion chamber deposits, and exhaust port blockage are also evaluated. The engine is set up with one cylinder supplied with a fuel and oil mixture made using the non-reference oil and the other with a fuel and oil mixture using the benchmark reference oil. The test is normally run twice, exchanging the oils between cylinders for the second run. Each run is performed on a 25-min part throttle 5-min idle cycle, with a 60-min shutdown after each 150 min of running time. Total running time per single test is normally 20 h.
5. Significance and Use
5.1 This test method is primarily intended for the evaluation of lubricants for use in two-stroke-cycle engines of high specific output.
NOTE 1 - If the test method is being used to satisfy a portion of Specification D4859, refer to the specification for the pass-fail criteria.
