The following Quote is from the SBD website Suzuki Hayabusa dry sump kit installation intructions
"It is beneficial to use this dry sump system with a completely sealed engine breather,
however this can ONLY be done if your particular engine creates a vacuum. In order
to check this, a monometer needs to be connected to the engine breather and the
crankcase pressure measured.
With the engine running on either a Dyno, race track or similar and under full load a
vacuum should be present at all rpm.
Every engine varies, and as such it is vital to monitor the crankcase pressure in your
particular engine before attempting to blank the breather, if the crankcase pressure
is positive then the breather should under no circumstance be blanked or damage
will occur!
This is the responsibility of the customer, if you do not have the necessary
equipment to carry out this task, then we recommend the engine is left
breathing to the drysump tank, which in turn breathes through the catch tank
to atmosphere."
Hope this helps?
Matthew