To place this oil screen on the engine, simply push it from outside.
The cause of its loss is often an overpressure of oil. Recommends that the maximum level is 3/4 between minimum and maximum level. Indeed during accelerations prolonged pressure in the crankcase can do not to evacuate enough by the breather.
Check so that this breather (black hose which is located a the back of the engine) is not limited.
External diameter 25.00mm, minimum 24.80mm