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View Full Version : VS1 burping on CO2 but fine w/HPA


MVS1
10-09-2007, 10:05 PM
Got a friend that runs the local pb store that's had 2 VS1's that recently started failing to recock using CO2 but operate fine using HPA. Tried all the straight forward remedies, cleaning/lubing/checking air passages, differnet CO2 tanks,etc. no dice. It's got both of us pretty stumped. Anybody have any ideas?

The Pumper
10-10-2007, 10:56 AM
I'm not a VS1 expert or anything but did you check the the valve and such? Making sure the orings dont swell or anything.

Was there any leaks involved with this?

MVS1
10-10-2007, 12:29 PM
Yeah checked everything, and no leaks, on HPA it's solid as a rock.

The Pumper
10-10-2007, 12:40 PM
Hm..thats weird. I'd assume if HPA was fine, then CO2 would be too. Seeing how that the VS1 is able to run on both.

Master Tech
10-10-2007, 05:12 PM
What you're probably experiencing is blowback overpressure, this happens when the air pressure coming from your Co2 is too high from a warm tank that's full or a freshly filled tank that has almost all liquid Co2 in it.

What's happening is the striker is slamming back so hard when it re-cocks that the sear sometimes does not catch it. Also when the Co2 used for blowback does not vent out fast enough or completely out the vent hole it can keep the striker from making full contact with the valve for the next shot. This happens when your shooting fast and can be duplicated if you point your marker down and forced liquid Co2 into the valve.

Another cause maybe your striker spring is too hard or you adjusted your velocity adjuster too far in. This can also make the striker slip off the sear and not catch properly.

First thing to check is make sure your velocity adjuster is not too far in, then check if the marker has excessive liquid Co2 coming out of the barrel when you're shooting. Let the tank warm up a little and when you get it filled, let the store or field fill it for you slightly under the capacity of the tank to allow room for expansion.

Now these are just suggestions to what might be the cause of the problem and assuming that your marker is in proper working order and has been properly maitained. Lubed, O-rings are good and every screw is nicely tightend without any considerable amount of wear on the sear or sear spring.

MVS1
10-11-2007, 06:56 AM
Master Tech, that sounds like what most likely is going on, good call. I wonder if an anti-siphoned tank would make a difference...Either way I'll pass this on to the shop owner so he can get these issues resolved and have this for future knowledge. TNX!!

Master Tech
10-11-2007, 12:34 PM
You're Welcome...

Just make sure if have your tank anti-siphoned, that your having a certified airsmith do it for you and it's done correctly. There has to be a proper amount of torque and Loctite 262 (Red) when re-installing the valve back onto the tank.

I know it sounds a bit much to go through but if you think of the consequences when proper installation is not followed, that tank might as well be a missile and people have died because of this.

Play safe and be smart...

Kenny_McCormic
10-11-2007, 07:21 PM
Actually I heard you not supposed to use loctite as all tanks now have relief holes in them so if the valve does unscrew the tank will just vent out and loctite can plug the vents.

druid
10-11-2007, 11:25 PM
the CO2 tanks are still Locktited. HPA are not.

Master Tech
10-15-2007, 10:26 AM
Actually I heard you not supposed to use loctite as all tanks now have relief holes in them so if the valve does unscrew the tank will just vent out and loctite can plug the vents.

Yes, you're right on the part were Loctite can plug the hole but even if the vent hole was not plugged up by Loctite, it does not vent the Co2 fast enough either especially if you have a large tank like a 20oz.

(Torque alone when installing the valve is not enough to secure it to the tank, a sufficient amount of Loctite is an added security to prevent failure...)

If you still have a valve that uses a small vent hole on the threaded stem of the valve to relieve the Co2 in case it threads off the tank, GET RID OF IT!!!

The most updated tank valves have channels cut down the length of the stem or have much larger vent holes on both sides and the stem itself have been lengthened.