My Blue Streak leaks a bit right after pumping,but holds air after........

[ujmrider]

I have a 1971 Streak that i bought in nonworking condition 2 years ago. I bought a repair kit and valve tool and resealed it myself.The inlet valve supplied in the kit was different than the stock item.I didnt like the look of the new one, so i repaired the old one. I re used the brass disc and die cut a new rubber from a motorcycle inner tube. Since doing that it has worked great but it does something that puzzles me. immediately after pumping it leaks for about 5 - 7 seconds, then stops.You have to listen very close to hear the leak. When it stops after the those few seconds it will hold air for many days with no noticeable loss of power. Its very consistent in this, but heres the puzzling thing i just discovered. If I dont close close the pump after getting to the desired number of pumps - no leak whatsoever. Or if I open the pump again while i still hear the leak it stops immediately.. However closing the pump triggers the 5-7 seconds of leaking. Whats up with this ? i was always under the impression that if a pumper leaked it leaked like all the way down, slow or fast.

[bgmcgee]

Have you tried cocking it before pumping? It could possibly be the hammer is slightly keeping the valve open just a little until enoug pressure closes it off. Just my thought.

[ujmrider]

I just tried that and it doesnt make a difference. My habit has always been to pump first then cock,so it was worth a try. Im shooting this afternoon,out my window because its raining hard. i have cans hanging by wires from tree branches. the wind today ads a little challenge.

[ujmrider]

I just hada thought about my leak. Maybe its not my inlet seal,but possibly air escaping back past the pump cup from excess  headspace ? Once thats out,no more leak. What do you think guys? Im planning to find a really nice Blue Streak and send it to Mac 1 for the steroid treatment anyway. this old beater that im messing around with is just so accurate its incredible,even though it looks like it went to war.

[Rob112o]

Valve spring isn't pushing the poppet all the way flush. That's why after a few seconds of air escaping pass it, it eventually blows it into place.

[Habanero69er]

Get yourself some Secret Sauce & lube up the gun. Put several drops on the piston & pivot points, cock it, then pump it up 4-5 pumps dry fire it to work the Sauce through the internals. After a couple times doing that, pump it up again & lean it in the corner over night to allow the Sauce to work it's way into the guns seals. Even if it doesn't cure this issue, you're still going to need lubricant to maintain the gun in the future & Secret Sauce is made just for pumpers. It won't harm the seals & won't gunk up the insides.