Motorcycle Repair: blow back, crank case vent, head gasket

Question
QUESTION: Hi Mike, I own a 89 flhtc, 1340 evo. Im experiencing excessive blow back, about a qrt in 100 miles when ridden at high rmp. Im contemplating to have the engine rebuilt. Would that take care of the problem. I had the pistons and rings changed during a repair of a head gasket about 5000 miles ago, the bike has only 30,000. whats your suggestion.

ANSWER: When you say blowback are you refering to oil coming out the vent?
Mike

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

QUESTION: yes, im refering to oil coming out of the hose that  comes from the crankcase  that leads to the air filter.The bike is runnning great, good power and response. other than this excessive oil splilage at high rmp, the bike runs impressively for a 20 yr old bike.

Answer
There are two possible reasons for this problem. One is the crank case vent is work and oil is getting past it. You would have to remove it and mic the hole it goes in. the other would be that the oil pump is worn and the return side of the oil pump is not pumping the oil back fast enough and oil is being help int he bottom end of the bike
Good luck and happy riding
Mike