How to set Harley Davidson Evo breather gear end play

[@intheshell35ify]

What the heck is a "breather gear"?!?!? Don't tell me harley needs gears to keep blowby from spraying like a tomcat.

[@willcountypowersports6338]

The breather gear controls the air circulation through the engine and aids in controlling the oil flow as well. when the pistons are moving down, the breather gear is open, allowing the flow of scavanged oil from the flywheels to be blown into the cam chest, oiling the cam, cam drive and lifters, settling in the bottom of the cam chest at the oil pump suction to be sent to the filter and then back to the oil bag. as the pistons move up, the breather gear closes, inhibiting reverse flow of the oil and air.

[@intheshell35ify]

@willcountypowersports6338 wait...it uses positive crankcase pressure to lube the valvetrain?? I'm speechless. (Thank you for the detailed explanation.)