need some help with a 13xx...

[lillysdad621]

I am having a bit of an issue with one of my builds... when i pump the gun, it seems to take only one pump as when you open the arm to pump a second time, it actually gets pushed open as if under pressure... and it does not matter how many times you pump it... it seems only to take one pump... any ideas where to look? If i dissasemble and put together, all seems ok. It works for one shot, then back to that "only one pump" capacity...

[K.O.]

Intake poppet...

[Big Bore Bart]

   Check the check    Something is interfering with the check poppet's seal.    Or the poppet is binding/cocking in the valve.           Possibly the spring is not square on the end?

[lillysdad621]

the poppet has a flat stepped side and a bevelled side... which one goes to the intake hole side?

[lillysdad621]

also i have a long poppet and a short one... would the long one raise the pressure inside the valve at the same amount of pumps???

[lillysdad621]

and K.O... your guns have a flat top setup???

[Big Bore Bart]

  Beveled and  the long one will raise more pressure.

[lillysdad621]

back to the bench...

[K.O.]

and K.O... your guns have a flat top setup???

no they do not,

the PC77 had to long of a nose on the valve,

ground it down till valve and cup fit perfect.

then shimmed pump cup, was not drilled for cross pin and still is not.

The 1322 the valve nose and cup came matched but cup needed shimmed to seat against valve face.

[K.O.]

Except for roll pins, guitar pick shims, and a screw eye front sight (PC77) all parts are Crosman.

[lillysdad621]

shim inside where the cup sits in the plastic piston??? thanks by the way... it worked!!! i over oiled it and it was sticking. cleaned up, flattened the spring and now it works again... if i could find the transfer port i can finish it up... (cat jumped on bench, knocking over cup of parts... grrr...) any idea on what to use as a interim transfer port while i order another from crosman???

[BillK]

Enter the poly tube mod.  http://www.gatewaytoairguns.org/GTA/index.php?topic=58060.msg555939#new

[K.O.]

shim inside where the cup sits in the plastic piston???

yep
the cup is the gage for how tight you have it shimmed.

the valve will leave a slight (not deep) impression in the cup when its right.