GTA
All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => China/Asian AirGun Gate => Topic started by: Ultramarine on November 26, 2018, 09:23:54 AM
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Got to admit I need some help.
I tried more than once to disassemble my Artemis from Krale Schietsport which is, except the intersect between the forearm and the shoulder stock, exactly the same rifle as the Seneca Dragonfly.
I could remove the trigger mechanism, have access to the intake port but never could I reach the valve system in its whole, in order to cure my problem which is a significant hissing sound at every shot, revealing some unidentified damaged O'ring. I tried to push it in the pump tube from both sides, fore or aft, with the help of a wooden stick but I failed. As this rifle is pleasant and accurate, I don't want to damage it so I'm looking for possible help : has anyone in GTA community disassembled this rifle and, if so, could he (or she) tell me how to extract this darn valve stuff?
I'd be highly grateful! ;D
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Tried to go farther disassembling the rifle and indeed I could, but with no useful result, as I couldn't extract the valve. :-\
As pics often say more than words, here's the "thing". The valve is firmly stuck in the pump tube and I just can't imagine how I could extract it, as there's no more screw, pin or anything else I could use for this.
Should I insert a wood stick and gently hit it with a hammer ?? And if so, in which direction. I'm a bit reluctant to damage anything.
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Have you tried a trick we use on old sheridans, by pumping a stroke with the pump the pressure usually forces the valve out the rear?
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I would go in the direction with the least amount of holes so as not to nick o rings.
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Sorry I cant help. Sounds like your the trail blazing pioneer with this gun.
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Here is an exploded view found on Pyramid Air Website.
(https://www.pyramydair.com/images/schematics/sy/Dragonfly-expoded-view.png)
https://www.pyramydair.com/images/schematics/sy/Dragonfly-expoded-view.png
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A few hours later of a hard tinkering work : I failed again!!!
I could extract the valve, I disassembled it, changed the damaged O'rings, the ones I thought to be the cause of my troubles, then I put the whole jigsaw puzzle back. Not a piece of cake.
Second shot : same infamous hissing. I cocked the hammer, pumped 4 strokes and waited 1/4 of an hour : no compression at all, all the air had leaked.
Now let me have a pause, at least just to comply with the forum rules concerning rude language... >:( :o >:( I still have to understand how those valve work.
CU later.
PS : to all 3 of you, thanks. I feel I'm not alone ;)
Back_Roads : the only way to extract the valve is forward, so you have to push it from the trigger side, which means a few things to deal with... as for the exploded view, I had printed it and kept it close. Though sometimes esoteric to me, way useful.
Avator : as I've just said, no altenative.
Paulus : thanks for your compliment but the snow really sticks to my snow shoes :P
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Some day I will have a seal let go and will have you to thank for the info and trial and tribulation you went through to fix it.
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Some day I will have a seal let go and will have you to thank for the info and trial and tribulation you went through to fix it.
Big +1 on this!
Not sound patronizing, but what are the contact surfaces that seal the pressure chamber? Where the air enters the chamber?
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Some jeweler files should clean the burrs around the holes. Then put some silicone grease on the o rings and use a plastic pick to help coax the o rings past the holes. I know, it's tedious but, it works.
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No more problems with different holes in the pump tube : I sanded them the way did with my Beeman P17 2 years ago and it's been OK until now.And the "new" O'rings, the ones I put on the valve body yesterday, look as brand new as they should.
But the heck if I understand how the valve works... :(
I took a new pic once I disassembled it, once again. As you may see, it seems to match with the exploded view, except that it shows 4 O'rings and I could find only 3 on my valve and there's no place I could put a 4th one. May be the problem lies in the "valve" itself (piece 48 on the exploded view) and as they provide a spare one, I'll use it.
BTW, my english being limited and my technical vocabulary being worse, how do you call the "whole thing" ? I'd call that an air cartrige but there's surely a more appropriate term.
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The complete unit is just referred to as the valve.
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I'm surely going the wrong way, and passing aside something important : I changed all the O'rings, changed that small piece of plastic called 'the valve", checked all I could, cleaned and cautiously reassembled everything .
At the first pump stroke, I knew something was going wrong as it was too smooth and easy. The following strokes were as easy and the rifle made a gentle puff when I shot it. No compression.
Now I'm going to wait for someone having the same problem, and who will cure it and explain how he did. Till then, I'll let that chinese beauty sleep, as long as she needs.
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Do you cock it before you pump, if you do then the poppet must not be seating in the valve, that would be the stem with the plastic plug on the end of it that is hit by the hammer when shooting. If all o-rings ar good, thats the only place that could leak. If the poppet is leaking you might try gently using some bore bright at the seal area and use a hand drill to spin it both directions, do this gently. If you attach a balloon to the end of the barrel and it blows up when pumping with the bolt closed, then it has to be the poppet. Regards, Tom
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Thanks a lot Tom,
I'm not sure I could understand everything you told me so I'll allow myself to try "translating" it in non expert terms :
1) This rifle needs to be cocked to allow the air being compressed in the valve unit. When you don't cock it, it makes some funny "burps", period. This happened until the valve unit leaked : now it doesn't release a sound.
2) If I'm not wrong, you consider the plastic poppet might not seat properly and you advise to gently polish the internal convex conical end facing the intake port. Why not, but how could have this "conical end" got damaged with a plastic poppet ; and there's been no difference with a brand new poppet and a cleaned valve internal.
3) I'll try the balloon trick, because it should actually show in which direction the air leaks ; and because I won't need disassembling the rifle once more!!!
Regards,
Yves
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I had a problem something like this on a 392, but it occurred after I had done a reseal on my air valve.
When I put the valve back in the chamber and put the gun back in the stock and tightened the air valve and stock bolt back down, air was by passing the valve on pumping.
I remembered reading some chambers on 392’s were a bit oversized and allowed air to pass over the seals on the valve.
I was going to take it apart again and try to put dental floss under the seals to maybe poof them up a bit.
Before trying that though I just backed the stock screw out 1/4 turn and that did the trick!
I put some lock tight on the screw, tightened it down again, then backed off about a 1/4 turn till it started to pump and hold air, and it’s still working a year later and after thousands of shots.
If the valve on your dragonfly is held by the stock screw, or any screw at all, you might give it try?
Maybe it could be just that simple.
I did have a bad poppet originally causing a leak, but after replacing that, I knew it had be the valve not sealing.... I got lucky and the screw tension took care of it😁.
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There's a time for tinkering and a time for cogitation, if not meditation. As I was doubtful about the way this valve functions, I spent some moments to try understanding it. In the meanwhile, I had tried the "balloon test" with the cut finger of a latex glove I sometimes use when tinkering (the latex glove, not its cut finger). It inflated slowly so obviously showed the leaking went to the barrel, which means the issue isn't located at the intake valve.
So I might be wrong but I considered there were only 2 other ways the compressed air could leak : the exhaust port and the hole of the exhaust valve pin. This last one is very thin and is supposed be properly sealed by the exhaust valve core. Moreover, any air leaking from there would not go into the barrel, I mean enough to inflate a balloon.
So I had a weird idea, the kind of which could make experts smile : what prevents the air to be compressed in the valve unit when the rifle isn't cocked is the constant pressure of the hammer on the exhaust valve pin, pushed by the hammer spring. This spring is indeed MUCH stronger than the valve spring. In contrary to what I do whith my Crosman 2100, I do not keep my LR700W valve compressed, for I should cock the rifle for this and keep the hammer spring compressed, too, and I didn't want to weaken it.
Thus, it's the valve spring, a light one, that stays compressed... by the stronger hammer spring. Then couldn't this light valve spring slowly get weak enough so that it couldn't keep the exaust valve pin properly closed ? I made a (very) coarse scheme of the valve unit just to illustrate this hypothesis.
I'm going to cock the rifle during a whole night and try a new "ballon test" the next morning. May be it won't be long enough to let the valve spring recover its original strenght but I'll have tried...
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The push from the hammer spring is minimal compared to the push of the compressed air. You might try removing the valve, splitting it, put some light abrasive where the poppet seals and chuck a hand drill to the stem that sticks out and spin it both directions pulling very lightly on the drill, it doesn't take much. When done properly, you should be able to see a pattern in the valve where the abrasion occurred, it should be even. Regards, Tom
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You're obviously right Tom, and that's what I'll do... later on.
Last attempt was a complete fail : I did the balloon test once more, after I had let the rifle cocked for about 2 hours. When pumping, the balloon got a bit inflated, but really not too much. Could have been positive, revealing a smaller leak, although the pumping effort was really easy. But when I shot, the only sound was the hammer hitting the valve pin. So the air from the valve flee where it wants.
I won't say I give up, but I'm going let some time pass... and then I'll try your solution.
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if it's leaking down the barrel your stem seal is allowing air past it
strip clean and inspect for damage possibly replace stem seal
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Ped,
As you may have guessed reading me, I'm sometimes fighting for an acceptable english, but I also miss a big part of technical vocabulary, though being a GTA fan, not only member.
So, refering to the Seneca Dragonfly exploded view above mentionned, could you tell me what's the "stem" and its seal ? Is it what they call "exhaust valve pin". If so, as soon as I have time, I'll try Tkerrigan's trick, as the exhaust valve core (it's how they call it) doesn't seem to have any seal.
Regards,
Yves
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part no 46 Yves the white Teflon taper is what seals in the valve and will be the part that is leaking
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Thanks Ped, I had guessed it right (phew!) and I tried the solution Tom suggested.
It took me some time. Not the solution, but disassembling and reassembling. And two "nicked" screws now, one on the pump axis cover cap and the other one in the small metal piece which helps to place the shoulder stock properly...
Well, my first test drove me quite optimistic : pumping was normally hard and I could hear no "hiss" when dry firing. Then I pumped 6 times and let the rifle for half and hour. Alas, poor Yago Yves, the only sound I could here, once again, was the hammer hitting the valve! ;D
May be I just didn't polish that teflon taper enough. Or could it be the other taper, the one of the intake valve? I'll do that later on.
Regards,
Yves
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Your drawing was very good! I kept it as one day I might need it.
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Thanks Paulus but you'd better refer to the pic I attached to the post I sent on December 2nd, 'cause I didn't locate the exhaust port properly. I attach it to this post again.
BTW, I'm going to put that rifle in a locker for a while : tried to shoot this morning, it hissed like an angry snake and wouldn't keep pressure >:(. I'm fed up, and I'm not going to spend more hours looking for what causes that *?%>>**^!lof a leaking.
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The first air gun I ever worked on was a Crosman 180. A CO2 gun, but the same type valve as a pneumatic. Soon after my reseal job, it began to leak. After disassembling again, I closely examined the seating surface of the valve stem and found a tiny crumb of metal stuck in it. This is a hard delrin or nylon type plastic. The offending bit was invisible without magnification. After I picked it out, there was a tiny pit where it had been pressed into the plastic. Chucked the stem in a drill and carefully spun the seat against fine sandpaper till it was smooth again. The gun has been fine ever since, it is one of my favorite shooters.
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Thanks Terry,
I'll keep this in mind until I unburry this Snow Peak rifle from its locker. Your advice is close to Tom's one and I can be but heedful to it.
But where's the hissing sound coming from ? Could it be the improperly cured intake poppet ? Or a big leak at the exhaust port ? Though the valve unit position looks perfect, "35 Shooter's" observation about it troubled me.
I have to admit I'm going to let things rest till I can read an actual intervention report on this valve unit. Don't wan't (for the moment) wrap the rifle on a tree trunk, according to the consecrated formula (I wouldn't be able to do that, anyway. Still expecting a video showing such a performance ;)).
Regards,
Yves
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Yves, Sorry to learn of this struggle. Thankfully I have not needed to address any valve issues, so I can't help. Just letting you know I feel your frustration. Hope it comes together for you when you go in again. I'll probably need help on it someday also.
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Should have mentionned that these last days the intake valve stopped leaking and the rifle almost stopped hissing. More important, I went back to a real decent accuracy. I conclude the combined advises of TKerrigan and TerryM brought this rifle back to life. Thanks a big bunch !
Now the bolt is still jumping at every shot which, if I'm not wrong, means that I should check the bolt seal. b*ù&#ùt!!! I'll wait till next year to play with this.