Motorcycle Repair: oil leak

Question
QUESTION: I have a shovel and when I am riding oil will purge from the oil tank and blow all over the back of the bike.  It does not leak while engine is idol. Could I be getting a pressure in the oil tank some how?

ANSWER: When you say oil is purging out of the oil tank, you mean it is coming out of the fill around the dipstick? How much oil comes out and what year is it?
Mike

---------- FOLLOW-UP ----------

QUESTION: Mike,  sorry I  just noticed your response.  it is a 1981 and it comes out around the fil ler cap.  I  have changed cap and even made a custom one on a  lathe

Answer
You never said how is coming out, but a couple of reasons could be that you have the tank overfilled or the rubber boot on the dipstick is not sealing. There is really no way that the tank can become pressurized and if it did the dipstick would pop out.
Mike