FX2000 or Tarantula keeps breaking valve pins

[fusion]

Hello,
I have an FX2000 in .22 that I’ve had since 2003. I don’t shoot it much because it keeps breaking the main valve pin. The pin breaks where the pin is cut down to hold the very small o-ring.
I get 1000 to 2000 shots and the pin breaks. This will be the 4th time I’ve replaced it.
Everything inside looks normal, so I’m not sure what is causing this problem.
Has anyone else had this problem? How did you fix it?
Thanks!
Mike

 

[willy]

O" Jusis"" i love those rifles"old school all the way"Man maybe to much tension on the hammer spring?maybe run it over a crony and see what it does?then back it off until it starts to drop in val.

 

[towle]

Is the main valve seat OK? - I had one fail, was sitting crooked in the seat at that might put sideways pressure on the valve stem, it was a FX Cutlas but same parts as the FX2000

 

[Feinwerk]

Some good ideas here already. I had a somewhat similar experience with my Edgun r5m. The regulator was creeping and partially locking the valve and I kept dialing up the hammer spring tension to compensate. Once I restored my velocity, I was beating the valve so hard that it broke after about 20 shots.

Carefully examine the face of the valve stem where the hammer strikes it. Has it been mushroomed at all? This would indicate excess impact forces. Has it been flattened in a plane that is not perpendicular to the long axis of the stem? This might indicate problems in geometry and the hammer not striking square.

I'm not familiar with the mechanicals of the tarantula but going by the name, 2000, I suppose that was the year of its manufacture? And therefore it is probably not regulated?

If it is regulated, definitely pull out the reg and reseal it and then re-examine the appropriate Hammer tension. You may want to consider a lighter pellet and lower power tune if it had been previously set up for highest possible power.

I would also disassemble the valve and check the valve return spring to make sure it is not broken and that there is no debris that would prevent the valve from moving properly during opening. Is it the factory valve return spring or has it been replaced with a stronger one?

That O-ring gland is certainly a tremendous stress concentration in that valve stem. Anything that causes sideways load on it would make it fatigue. Have a close look at the face of the hammer where it strikes the stem and make sure it is flat and square and strikes the PIN directly on its axis and not at an angle.

GL, let us know what you find.

 

[fusion]

I ordered a new valve pin, and disassembled the gun last night. The valve body looked OK, but the hole the pin goes though looked a little bit worn. The valve pin seemed a bit loose. Maybe this is why there was a side load on the pin. I contacted FX for a replacement valve body and seal. I never thought they would have one being a 20 year old gun. Well, they allowed me to order one and the price wasn't unreasonable. I hope it is in stock. I'm hopeful this will correct the problem.

 

[Feinwerk]

Cool, that's great that you can still get that part.