GTA

Airguns by Make and Model => Crosman Airguns => Topic started by: lillysdad621 on December 23, 2013, 10:46:50 PM

Title: need some help with a 13xx...
Post by: lillysdad621 on December 23, 2013, 10:46:50 PM
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...
Title: Re: need some help with a 13xx...
Post by: K.O. on December 23, 2013, 10:57:22 PM
Intake poppet...
Title: Re: need some help with a 13xx...
Post by: Big Bore Bart on December 23, 2013, 10:58:20 PM
   Check the check ;D   Something is interfering with the check poppet's seal.:o    Or the poppet is binding/cocking in the valve.           Possibly the spring is not square on the end?
Title: Re: need some help with a 13xx...
Post by: lillysdad621 on December 23, 2013, 11:06:21 PM
the poppet has a flat stepped side and a bevelled side... which one goes to the intake hole side?
Title: Re: need some help with a 13xx...
Post by: lillysdad621 on December 23, 2013, 11:07:29 PM
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???
Title: Re: need some help with a 13xx...
Post by: lillysdad621 on December 23, 2013, 11:08:37 PM
and K.O... your guns have a flat top setup???
Title: Re: need some help with a 13xx...
Post by: Big Bore Bart on December 23, 2013, 11:12:42 PM
  Beveled and  the long one will raise more pressure. ;D
Title: Re: need some help with a 13xx...
Post by: lillysdad621 on December 23, 2013, 11:21:31 PM
back to the bench...
Title: Re: need some help with a 13xx...
Post by: K.O. on December 23, 2013, 11:23:41 PM
Quote from: lillysdad621 on December 23, 2013, 11:08:37 PM
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.
Title: Re: need some help with a 13xx...
Post by: K.O. on December 24, 2013, 12:43:42 AM
Except for roll pins, guitar pick shims, and a screw eye front sight (PC77) all parts are Crosman.
Title: Re: need some help with a 13xx...
Post by: lillysdad621 on December 24, 2013, 12:47:23 AM
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???
Title: Re: need some help with a 13xx...
Post by: BillK on December 24, 2013, 12:55:30 AM
Enter the poly tube mod.  http://www.gatewaytoairguns.org/GTA/index.php?topic=58060.msg555939#new (http://www.gatewaytoairguns.org/GTA/index.php?topic=58060.msg555939#new)
Title: Re: need some help with a 13xx...
Post by: K.O. on December 24, 2013, 01:13:17 AM
Quote from: lillysdad621 on December 24, 2013, 12:47:23 AM
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.