Bubbletest

[nan00k]

Hard starting led me to bubble test, made manifold 'cap' out of 1/2" ali plate, valve and sealed with silicone gasket. Foot pump shows 10lb but goes down as fast as it goes up, can't even get a hint of bubbles anywhere. Checked with pushrods removed. The heads have been off and re lapped valve seats and checked by filling combustion chamber with white spirit and no sign of leaks, thought I had also checked inlet ports as well but maybe hazy memory. So that leaves me with worn guides as only possible culprit or have I missed something?

[1950Panhead]

Remove spark plugs, release push rod covers, go to 20 psi, listen for leaks.

[socalrider]

You need the constant pressure provided by using a compressor. Dont think a foot put will do it but i could be wrong.

[Excalibur]

Compressor with regulator at 15psi. My set up..
Undoubtedly there will always be some some pressure loss up the guides.
Hope this helps.

[nan00k]

"use a compressor", seems like a no brainer, i'll get my coat.