Hi guys. I'm working on a Cricket for a friend. He complained of a leak that would take the Cricket from full to empty in ~24 hours. It's about 4 years old, with no other health issues, and is in great condition.
Once I got the Cricket, I filled it with my friends HPA tank to the usual approximate mark on the reservoir gauge. I heard a barely audible hiss coming from the front of the reservoir between PN-20 and PN-1. I shot the rifle a couple of times to check overall function and set it aside for a day. Once the reservoir was empty, I unscrewed PN-20 to replace PN-8, because I assumed that this would be the main culprit for the leak. Joe B. also convinced me to give this a try.
After replacing the o-ring, I applied silicone grease to the ring and screwed the assembly back onto the reservoir. The assembly wants to bottom at the end of the threads inside PN-1, but this takes the fill port hole too deep into the reservoir for the fill probe to be fully inserted without hitting the front of the stock. So, once I was ready to put the stock back onto the rifle. I backed the assembly out almost one turn, which allowed the fill probe to be fully inserted and one land of the hex portion of the probe to just barely rub on PN-1. This is the maximum depth PN-20 can be screwed into the reservoir. With the stock on, the first time I attempted to fill the reservoir, there was a major leak around the fill port area. I then took the stock off, fully threaded PN-20 into PN-1, and tried filling again. The leak remained.
PN-8 o-ring is the only change I made. It's the correct size and material, and there is no way that I nicked or deformed the ring on installation. I tried a second ring and got the same result. The leak sounds slightly muffled, like it's not coming from the probe or fill port. It sounds as if it's coming from the gauge.
How do I remove the gauge (PN 20) from the end plug (PN 23)? I'd like to try replacing the rings at PN-19 and PN-11. The spring action of the cover prevents either hand or wrench from accessing the gauge.
Also, what are the functions of the screw and ring at PN-18 and PN-19?
I’ve done it before in another way but that wouldn’t be recommended.
The way you described the fill cap is the correct amount to screw it back. You can back that out until the probe isn’t restricted from entering the entry for the fill hole and it will be fine
The small screw and oring (18 & 19) effectively are a metering system to control how quickly the reservoir if filled with air and also seal the entry of the fill acting as a check-valve. When changing this oring I suggest bottoming the screw and backing off 1.75 turns. Definitely change this oring as it’s a more common leak point than the gauge oring.
Hello Fouo, my best advice to you is the entire gun needs to be resealed, especially the internal reg 0-rings. For you to change just this 0-ring or that will mean you will be chasing your tail for a long time. All 0-rings will leak eventually. When I rebuild a Cricket I not only replace all 0-rings but go through the entire gun to get things as good or better than new. About half or more of the Cricket's I get to rebuild are from people who tried to do it themselves.
Hello Fouo, my best advice to you is the entire gun needs to be resealed, especially the internal reg 0-rings. For you to change just this 0-ring or that will mean you will be chasing your tail for a long time. All 0-rings will leak eventually. When I rebuild a Cricket I not only replace all 0-rings but go through the entire gun to get things as good or better than new. About half or more of the Cricket's I get to rebuild are from people who tried to do it themselves.
Charlie Frear, Georgia Airguns
georgiaairguns.net
To each his own. I’ve resealed a lot of guns and never had to send one in to a dealer or repair guru for a leak.
I’ve done it before in another way but that wouldn’t be recommended.
The way you described the fill cap is the correct amount to screw it back. You can back that out until the probe isn’t restricted from entering the entry for the fill hole and it will be fine
The small screw and oring (18 & 19) effectively are a metering system to control how quickly the reservoir if filled with air and also seal the entry of the fill acting as a check-valve. When changing this oring I suggest bottoming the screw and backing off 1.75 turns. Definitely change this oring as it’s a more common leak point than the gauge oring.
Thank you, very much, for this help. Where can I find that tool? Why did you find reason to remove the gauge?
There is a small hole to the side of the check-valve that you mentioned, maybe 1.5mm dia., but I cannot find any other description or explanation for it in the simple diagram. What is behind this hole? Why does it seem to bypass the check valve? Could there be a diaphragm or burst disc in the hole to act as a over pressure release? If so, could this be the cause of my leak?
I'm going to try replacing the small o-ring on that screw and backing out, as you recommend, and I'll report back on how that works. Thanks, again, for the help.
Hello Fouo, my best advice to you is the entire gun needs to be resealed, especially the internal reg 0-rings. For you to change just this 0-ring or that will mean you will be chasing your tail for a long time. All 0-rings will leak eventually. When I rebuild a Cricket I not only replace all 0-rings but go through the entire gun to get things as good or better than new. About half or more of the Cricket's I get to rebuild are from people who tried to do it themselves.
Charlie Frear, Georgia Airguns
georgiaairguns.net
Mr. Frear, thanks for the suggestion. I'm familiar with the limitations of the rings, and I'm usually comfortable with their maintenance. Your approach is definitely the most thorough and would rule out other leaks. However, at this time, I think that the only real issue is at the front of the rifle and both me and the owner would accept getting the reservoir back to holding a charge with minimal acceptable leakage. When the time comes, I'm hoping to buy a kit from a retailer for that task, as I'm now looking at buying a couple hundred rings just to get the handful I actually need. Thanks for your help.
I’ve done it before in another way but that wouldn’t be recommended.
The way you described the fill cap is the correct amount to screw it back. You can back that out until the probe isn’t restricted from entering the entry for the fill hole and it will be fine
The small screw and oring (18 & 19) effectively are a metering system to control how quickly the reservoir if filled with air and also seal the entry of the fill acting as a check-valve. When changing this oring I suggest bottoming the screw and backing off 1.75 turns. Definitely change this oring as it’s a more common leak point than the gauge oring.
Thank you, very much, for this help. Where can I find that tool? Why did you find reason to remove the gauge?
There is a small hole to the side of the check-valve that you mentioned, maybe 1.5mm dia., but I cannot find any other description or explanation for it in the simple diagram. What is behind this hole? Why does it seem to bypass the check valve? Could there be a diaphragm or burst disc in the hole to act as a over pressure release? If so, could this be the cause of my leak?
I'm going to try replacing the small o-ring on that screw and backing out, as you recommend, and I'll report back on how that works. Thanks, again, for the help.
Ebay is where I've seen the tool. I removed the gauge to cut a few coils off the spring that forced the fill cap closed. I think the spring is a bit too tight.
There is no burst disc, diaphragm or as I've heard some suggest charcoal filter there. The Kalibrgun Cricket is a very simple yet robust and proven design. Once you get in there you will understand why and how it all works. The holes are all there as a "tattletale" to find leaks if and when they may arise.
More than likely your leak is coming from the small oring at 18&19. Replace it and do the 1.75 turn. 1 turn gets you slow fill, 1.5 turns gets you a medium fill. I personally prefer filling a bit quicker with the 1.75. While you have it depressurized, explore the systems workings. Great PCPs.
Has anyone found a place that has the Gauge removal tool? My .25 losses air from 200 bar down to 140 bar and is coming from under the gauge. After talking to Ernest he mentioned the oring under the gauge being it was last replaced in 14’ when he tuned it. Thanks for any help, and forgive jumping on the thread for my own use. (I should add I am on the BOI for years, just have not been on the new Yellow much)
To fix a leak it's a good idea to first find where it is.
On the front AT cap on a Cricket the 4 possible points of leak could be :
1) The large high pressure O-ring, leak out of its indicator hole. 2) The check valve/fill O-ring, install the fill probe into the fill port and fill port end with soapy water.
In maintaining this fill valve O-ring on all my PCP's twice a year I use a syringe to place a small amount of silicone grease directly into the fill inlet inside of the fill port. With the gun pointing up blast fill with a couple of good burst of air with your SCUBA tank this will send the lube onto this little O-ring inside. My EdGun had a fill valve leak a couple of months ago and I fix it with this method and till today it hasn't leaked again.
3) If the 2 above passes then its got to be the gauge O-ring.
and or 4) The gauge itself but not often.
For the Cricket gauge removal socket John he maybe still making them for sale also. viewtopic.php?f=33&t=30282&p=305443&hilit=cricket+gauge+socket#p305443
OR with some tools u can make one yourself, it not hard to do.
Fell free to contact me if you need any further assistance with maintaining your Cricket.
Thanks
Charlie Frear, Georgia Airguns
georgiaairguns.net
If it comes to needing outside help Charlie is fantastic to work with! He did a "Power Tune' on my Cricket. Not an issue since. Great guy even just to chat with.
I’ve done it before in another way but that wouldn’t be recommended.
The way you described the fill cap is the correct amount to screw it back. You can back that out until the probe isn’t restricted from entering the entry for the fill hole and it will be fine
The small screw and oring (18 & 19) effectively are a metering system to control how quickly the reservoir if filled with air and also seal the entry of the fill acting as a check-valve. When changing this oring I suggest bottoming the screw and backing off 1.75 turns. Definitely change this oring as it’s a more common leak point than the gauge oring.
Sorry for the ancient thread revival.
Regarding the bolded info above (backing off the fill restrictor/check valve screw 1.75 turns)....does anyone know if this is accurate for the Cricket II too?
