Thanks for input. I used Twin Air bio power spray for the filter. Seems to work fine, with the exception of that slightly too loud and high pitch "tamburine" noise at around 3500 rpm...makes the bike sound like a lawnmower
Need to next try another oil. On the upside I believe the engine is now running better. I did notice that the crank breather hose was dripping some oil to the front intake...and now since I redirected that to a minifilter, it naturally does not happen anymore. Or maybe it's just the effect of getting more air...dunno.