can anyone help
 

I have a 97 mule with the 620 cc motor. It kept blowing oil out the seal at the crankshaft on the fly wheel side.
took to a mechanic who said it was because of worn cylinders, so I had them bored out .40 installed new pistons and rings.
still blowing out! blew air in the oil pipe, came out top of motor at breather valve, blew air in the breather valve came out the oil stick.
So I think the crank case is being ventilated, but I noticed when at idle it puffs out a little air, but when revved up, not so much.
Any ideas
thanks