A good "quick and dirty" test. Definetly indicates more thorough (read
accurate) checking is in order.
The pop-pop is the exhaust attempting to suck air back up the pipe via
the burnt valve, which doesn't seal.
No, I doubt the air pump would inject enough air into the port to have
much if any effect on the POP-POP test
On Mon, 29 Dec 1997 16:16:29 -0800 Skye Poier <email@example.com>
>While looking through the (excellent!) Motorhead catalogue I noticed
>interesting 'dollar bill' test: take a bill and hold it against the
>pipe while running and if its pulled against the pipe 'snap snap' then
>you have incorrect valve timing or a burnt exhaust valve. Seems
>if the exhaust valve is open when the piston starts down, it would
>back up the exhaust pipe. At least, thats my amateur speculation.
>air pump not supply enough air?
>Is this a reliable method to use? A lot simpler than a blowdown test
>(although I'm inclined to believe not as accurate)