Put the transfer port back upside down...

[egillman]

I just finished putting my Crosman 66 back together after drilling out the exhaust port of the valve and the barrel to 9/64" for a little more flow.  This is the manually-cocking type of valve like later 760's and 2100's used.  I got it back together, pumped it 10 times, and fired.  All I got was a little "phut" sound and no air out the barrel.  I took it all apart, put a few pumps in, and manually tapped the valve.  BLAM!  All seals are good.  I put it back together, same result.  After several attempts, I looked carefully at the transfer port that connects the valve to the barrel.  Alas, I had put it back upside down!  I had essentially reduced the hole size from 1/8" to 0".  Once I put it back on correctly, everything worked fine.  I'm guessing at least ONE of you have done the same thing?

[darren]

nope never......you are the first and only one to do it

[Tommy]

But none of us will ever do it again.lol
Tommy

[brzryder]

Glad you found out what was wrong easy thing to do.Now you never said how it worked out did you gain or lose on the fps sometimes if you bore out the tp too much you lose fps?

[egillman]

I have also read that.  I have not checked the fps but it's on my list of things to do.