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Author Topic: Valve Leak?  (Read 1712 times)

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Valve Leak?
« on: February 06, 2008, 05:26:08 AM »
Hi all
I have a QB78 on which I have changed the stock for a 'lefty' thumb hole. I have polished the sear and the ports and changed the 'piston' in the valve for a taperd one with a screw shank to allow easy replacement of the face seal. About every 10 shots the gun 'dumps' gas out of the muzzle with the bolt closed. I guess it must be a problem with the valve not dealing with the differentual pressure. I have change seals, lubed the gas tube etc.etc. Any ideas on what to do, please?

Buzz
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Offline mikeiniowa

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RE: Valve Leak?
« Reply #1 on: February 06, 2008, 05:37:58 AM »
must have a very light spring in the valve or a super strong one for the striker, add to the valve spring or lighten the striker spring...don't shoot to quickly wait a bit between shots, could be freezing the stem seal making it leak......
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  • Guest
RE: Valve Leak?
« Reply #2 on: February 06, 2008, 07:33:54 AM »
Many thanks..will give that a try.
Buzz
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