I have a 1985 FXRC that has started to puke oil out of the breather on extended rides. Last summer was cruising up the highway around 70mph (3000-3200 rpm) for a couple of hours. Pulled over for a break, entire side of bike was coated with oil, wrapped pipes smoking like a Nascar blowup, oil puking all over hot engine. Checked oil tank, was full of foam. (Running Amsoil synthetic oil 20/50 with about 1000 miles on it) Trucked bike to shop. Told that oil was probably bad and to change to conventional oil. Did so. Short runs since, 30-50 miles, oil pressure usually runs about 12-13psi warmed up and cruising. Less that 500 miles on conventional oil, went for ride last night, 35 miles, about 65 degrees, half way through pressure dropped to 10 psi at speed. Checked oil back home, tank full of foam but not puking out. Anybody have any ideas, possible oil pump???