Engine oil seal set for Viper 125-200 cc motorcycles and similar (China, Minsk). The set includes the engine shaft oil seals. They keep oil in the crankcase and keep air from being drawn in, and on the crankshaft they maintain the vacuum.
Replace them when the engine is taken apart or if oil seeps at the shafts, pressure is lost and the revs are unstable. It is better to replace the whole set.
