All those K&B .61's have ghosts in them....they come that way from the factory. They
used to have a large surplus of ghosts, and that was the only way they could get rid
of the....ship 'em out.

Seriously though, I'm been running those engines for over 35 years....and I think it's
the chrome liner that does it, and it depends on how the engine shuts down. If the
engine were to run out of fuel, or lean out and die for some reason....it would be a hot
and dry shut down....the compression would seem low.

On the other hand, if you were running the engine on the ground and richened the
mixture way up before you shut it down....you would have a cool/wet shut down, that
would result in the feel of more compression because of the amount of oil left on the
cylinder wall.

Also you have to take into account how hot the engine is. The hotter it is, the more the
cylinder and liner will have expanded...cause a slightly larger ring gap, that will result
in a feel of lower compression.

So it's the amount of oil on the cylinder wall and the ring gap that effect the compression.

FBD.