Motorcycle Repair: A hose that is shooting out oil, vent hose, oil tank

Question
My dad has a 1986 full dressed classic, number 51 out of 650 or so.My question is when he tries to fire it up it, it shoots out oil from some hose that has obviously come undone.I cant find out where the hose goes nor can I see if there was a place for it.PLEASE HELP!
Thank you for your time,
Robert.

Answer
it is a crankcase vent hose at the rear of the motor on the right hand side. The crankcase is fill up with oil as the check ball in the oil pump is not seating correctly. and when the bike sits the oil passes the check ball and fills the lower crankcase full of oil. When the engine is started it pours out the crank vent hose. Put a pan under the bike and run motor untill oil stop coming out, Then check oil tank and top oil tank to the full mark. Johnny