Should oil be coming out of my crankcase pressure releif hose after running in 4th-6th gear for awhile?

What mileage has the bike done? Excessive crankcase ventilation is a sign of worn rings.....you will normally get some fumes from the crankcase as the oil heats up,this is normal,its drawn back into the inlet manifold to be burnt off.Don't plug it,you'll end up blowing a main seal....