Good for flow BUT with higher pressure and the fresh charge maybe pushed
out `cause your high transferduration of approx 130 degrees,this at low rpm.
You can reduce transferduration to reduce that but you get a narrower powerband
though.
The aim of transfers must be reshaped to enter more at back of barrel to reduce
lost of charge.
You can try in small steps and see what?s happening,maybe KX500 have to low crankcase compression stock.
crankcase volume at TDC/crankcase volume at TDC - cylinder volume is the formula.
I think a expansion chamber with steeper cones will do the jobb better and still have 130 degrees of inlet duration left.
//doordie