by RayK » Fri Mar 13, 2015 9:42 am
It is similar to the intake/exhause valves in an internal combustion engine.
poppet - plastic plug like thing that is on a steel valve stem (a thin rod which is hit by the hammer to fire the gun).
valve seat - the ring the face of the poppet presses against to seal the air in the air chamber. Below the valve seat is the flow path for the air to escape from the valve on a shot. From there, the air flows into the transfer port sleeve then into the barrel through the transfer port machined into the barrel.
Debris between the poppet face and the valve seat will cause it to leak.
Any mismatch between those two surfaces can also cause a leak.
You can put a polishing compound on this interface and run the valve stem in your drill or drill press while pulling pressure on the valve body to improve the seal/mate between the poppet face and valve seat. When done, you clean it all up really well then reassemble.
I hand problems with my XS60CPCP sealing. I bought an aftermarket delrin poppet from mountainair.com and polished it this way and it has sealed beautifully ever since. The stock Marauder poppets are better quality. Gen I valves have a ring lip on the valve seat. I don't know if the Gen II vaves do. The XISCO valves don't have one, so the poppet needs more help to seat well.
Ray
25 W-rod | 8 shots @ 70 FPE -2% | 3100 fill
25 M-rod | 40 shots @ 35 FPE -4% | 3100 fill
22 M-rod | 51 shots @ 25 FPE -4% | 3100 fill
17 M-rod | 60 shots @ 19 FPE -4% | 2500 fill
25 P_rod | 16 shots @ 28 FPE -4% | 2100 fill