Rob,
Flogging it could have caused it. I've seen other posts about adding lower end venting through the dipstick.ight be worth a try if the problem persists.
Davo
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If the only venting is thru the head, and from your reply, I suspect it is, I might try a couple of things up there. One is a reed type check valve to maintain a negative or zero pressure. That will help with any seals that might be getting tired. And also putting a coalescer in the line, which is little more than a piece of pot scrubber before the reed valve. Maybe just making the vent line loop upward under the tank first, with a coalescer would be sufficient to decrease the oil ejected out the vent pipe.
regards,
Rob
regards,
Rob