uriarc

Hello all, I am after a little advise / answers if possible. I have recently picked up a 1997 Thundercat with 28000 genuine miles on it. I have done approx 100 miles on it so far, but each time i have riden it, the next morning there has been an oil mark on the garage floor from the air box drain hose (about the size of a 50 pence peice). Can someone tell me WHY!!!!!