Oil tank vacuum - softail

[B.BEAR]

Noticed lately whenever I pull the dipstick on FXSTI after ride,there is a rush of air back in to tank or vacuum, is this OK?

 

[glider]

It shouldn't be a noticable thing. Check your lines and make sure they are all OK.

 

[B.BEAR]

Thanks Glider, thought I should add, - just got E-mail back from dealer service manager after your reply who advised - H.D. use positive and negative pressure to help scavenging from engine as it is a fully sealed system,(not really sure what that means) said all OK - I havent been riding Harleys long so not fully familiar with them yet

 

[glider]

True that they use pos and neg pressure but that is the result of the oil pump doing it's job and how it operates basically. There shouldn't be any noticable vacuum in the tank after it is shut off. It should equalize when the engine stops running.