Huben Any issues or problems with Huben gk1 please share your experience

25 cal with 25 grain pellets at 40 fpe
1 mag 9-10 fps spread
2 mags 25-30 fps spread.


22 cal with 25 grain pellets at 40 fpe
See pics

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If the valve swap doesn’t work, the only thing i can do … not to fix it but prove theres a issue. Swap the barrel/mags on both with each other.
i really believe it has something to do with the closing valve assembly. It does what it’s supposed to do allowing more air to pass as tank psi lowers but sooner than it should.
It operates great 35 down 30, slowly increases per shot till about 25 mpa before it opens up.
If i run it at say 20 fpe with a 30 fill it will do great 30 down to 25. Then spike at 20 mpa.
I dunno, ive had 3 different springs in there, no difference.
Up top … 3 valves. 2 strikers and multiple different springs… no difference.
Maybe something machined off within the block. Swapping the barrels will tell me a lot.
 
I have a theory. First valve i removed had white markings in 3 spots from the o-ring.
The 2nd valve was removed and it was sticking causing it to not close and slowly let out the air. This gun has never been right since day one. The only difference between it and the 25 now is the valve oring. The latest orings i got from Wolfiek group are black. I will see if i can post a video but the white oring is a little thicker. Its harder to slide the ring over the valve even with silicone oil. Theory is the firing valve is not cycling properly. Can imagine the white o-ring has a tighter hold when installed in the block.

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New valve. Same as with the one i lost.. its chamfered so you dont get that circular imprint from the washer. No vent/notches .. got my from AGT so dont know if its a older revision.
Anyone know if this is PEEK? saw it asked before but i dont recall the answer.
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You need a vent notch. The air bleeding into the firing valve closes it faster. Even a tiny one. As air goes into firing valve area to close firing valve, speed valve will open. As far as oring goes, I vote for the white urethane oring. Will deform less and drag less under pressure.
 
You need a vent notch. The air bleeding into the firing valve closes it faster. Even a tiny one. As air goes into firing valve area to close firing valve, speed valve will open. As far as oring goes, I vote for the white urethane oring. Will deform less and drag less under pressure.
It does have the notch on top if that is what you’re talking about?
Too late .. black o-ring installed.
Tomorrow will see if my theory was correct.
Next step is garbage can… haha jokimg.
 
Interesting, something i should of done way back. Swap the calipers over.
Ran the 25 cal barrel/mag on the 22 block.

22 cal as is 30 fpe
1 mag 25-30 FPS spread
2 mags 80+ FPS spread and climbing.

25 cal on 22 block 40 fpe
1 mag 21 FPS spread
2 mags 51 Fps Spread (peaked at shot 28 and then decreased)

25 cal as is 40 fpe
1 mag 10-15 FPS spread
2 mags 35-40 FPS spread

22 cal on 25 block 30 fpe
TBD

All the F’ing around with the 22 block and it looks like its the barrel/mag or caliber itself not playing well with the valving.
Still need to test the 22 cal barrel on 25 block. If the velocity spikes .. that will totally rule out the block as the issue. The 25 as is gets the best numbers.going to be interesting to see what it does with the 22 barrel.
 
Hard to believe that you’re having so much trouble with your GK1s.
I’ve had my 25 a couple of years and shoot almost daily.
Absolutely zero problems shooting 24 grain JTSs at 880fps and extremely accurate if I might add.
No jams ever!
As I mentioned in a post early on in this thread, “some people shouldn’t own a GK1”
 
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Hard to believe that you’re having so much trouble with your GK1s.
I’ve had my 25 a couple of years and shoot almost daily.
Absolutely zero problems shooting 24 grain JTSs at 880fps and extremely accurate if I might add.
No jams ever!
As I mentioned in a post early on in this thread, “some people shouldn’t own a GK1”
Is it the reading or comprehension the issue with some people? I HAVE 2 GK1’s, actually 2.5 if you count the .177 barrel/mag… but i dont recall mentioning that so. In almost every post of mine im comparing the two .. my 25 IS PERFECT with 0 issues. I just swapped the calipers and ran the 25 barrel on the 22 block and it shot great. That is where we are at now. Also ive replaced the main seals and valve o-ring in the 22 block for other issues i thought were related but were not .. not a easy task btw.
So its clear i am not just some novice that “shouldn’t own a GK1” smh
I also have a FX Pathera compact that was converted to a dynamic, 2 Avenge X’s, Fully modified Notos, and a AEA 50 cal Harpoon.
Also the guns that started my airgun addiction. Gamo arrow, Urban and 2 springers, 4 co2 pistols. No major issues with anything else but the 22 GK1 .
 
Hard to believe that you’re having so much trouble with your GK1s.
I’ve had my 25 a couple of years and shoot almost daily.
Absolutely zero problems shooting 24 grain JTSs at 880fps and extremely accurate if I might add.
No jams ever!
As I mentioned in a post early on in this thread, “some people shouldn’t own a GK1”
That's quite a silly thing to say. Just because you never had issues with it does not mean the gun is perfect in every way, or that every problem can be chalked up to user error.

GK1's are not identical clones. Each one comes out of the factory a little different. I have one of the earliest models, and mine happens to have a slightly oversized magazine, and therefore is a little more picky about ammo. It happens.
 
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