Rapidfire, ULT w NO shims

[cadams]

Hi All,

I broke the on/off pin in my stock XValve on/off assembly. So I bought a ULT upgrade and now I can't pull the trigger without rapid fire of shots. I have 0 shims in the ULT and it still rapid fires.

My setup: XValve, ULT, Lvl 10 installed on a classic rail and body. I have 3 trigger frames; I've tried all of them and I have the same result. The 3 trigger frames I have used are classic, proline, and hyperframe (20 bps board).

The hyperframe seems to run away least. but it still does. Any suggestions?

[211]

Whats your input pressure?

[cadams]

800, non-adjustable

[Hilltop Customs]

what do you mean by runaway? If you pull the trigger hard and keep it held in is it firing more than 1 shot? If thats the case its probably the top o-ring in the ULT.

[athomas]

It sounds like a bad top oring.

[cadams]

By runaway I mean it fires a rapid succession of shots for as long as I hold the trigger down. The shots are so fast, that I can't shoot 1 shot if had to. With the quickest trigger pull, I get at least 2 shots.

Its not the top ULT o Ring (the tiny one at the top that the pin slides through, yes?). 1st, the ULT is brand new out of the box. 2nd, I already replaced it with the spare that came in the kit. No effect.

The only thing that has changed between the working setup, andthis now non-working setup, is the ULT upgrade.

[Hilltop Customs]

yep, that is caused by the top oring in the on/off assembly not sealing. By the top o-ring we dont mean the black tiny one that goes around the thin part of the pin, but the larger white one that seals with the "head" of the pin. With the 2 body parts of the ULT assembled the o-ring is still visible on the part of the on/off that goes into the valve first.

If that oring is not there/damaged it allows air to constnatly flow through the on/off, which will cause the bolt to bounce back and forth between the spring pressure and the air pressure since nothing is stopping the air flow into the powertube.

[SchoolU101]

I think that's the one he already replaced.

How much friction is the o-ring putting on the pin? Does it seem sticky? Either way, add oil.

[Hilltop Customs]

idk he said pin slides through. The pin doesnt really slide through the top o-ring in just kindof bump seals against it when the trigger is pulled.

If the tiny black o-ring is bad you will hear a leak coming from the bottom of the valve/triggerframe. If the top o ring is missing/bad you will get rapid fire/bolt not fully resetting.

[michbich]

What's the length of the pin?

[cadams]

correct, I already replaced that one. The white one where the ULT meets the Xvalave, NOT the black one sandwiched inside the ULT. The one that was installed in the ULT brand new comparred to the spare one that I used to replace it; same issues, no difference between the 2 O rings. I guess its possible that both O rings are bad, but neither has ever been used, unlikely, but anything is possible I guess.

I am not supposed be using that double O ring setup from the old on/off too am I? I tried out of desperation (my thinking is along the same lines of all of you, leak where the on/off meets the Xvalve) but the ULT sticks out way too far and won't fit into the body.

My suspicion now is that the problem lies with the fact that I'm using the old 68 classic body and rail and maybe the thickness of the rail and body is too much. Where maybe theres too much distance between the sear and the ULT pin.

To clarrify my setup; I've owned an Automag for years. Started with a 68 Classic with Expansion chamber. I upgraded to the XValve and switch from CO2 to Air and used that setup, XValve on 68 classic, for years. Then I added a proline trigger and got this same problem, actually, so I went back to the stock 68 trigger. Then I got a hyperframe, and it worked fine. Then one day, during play, my trigger frame screw came loose, the body, rail, valve, all separated and resulted in my stock on/off pin getting decapitated. I didn't see the stock XValve on/off in the online catalog so I got the ULT to replace it. Its brand new, and I cannot get it to work no matter which trigger frame I use now. Maybe this adds some insight into the problem?

[cadams]

I don't have the pin in front of me, but its the standard ULT pin that comes with the kit. I have not shaved or modified it in any way.

I have considered shaving it though. The rapid fire problem increases as I add shims so length of the pin may be key. But how would I shave anything off that thing? its so fragile.

[Hilltop Customs]

Your right the double orings used with the original on/off are not used with the ult.

adding shims has a similar effect to shortening the pin, so shortening the pin wont help. Since that oring is in the top, it sounds almost as if your pin is too short. Like michbich said is there any way you could measure it?

Also check the exterior o-ring on the top of the ULT(the one that contacts the valve), if it has any slices, it could be causing the problem too.

[cadams]

0.74 inches.

Some pictures, if it helps

[SchoolU101]

It's supposed to be 0.75". I would think that 0.74" would be close enough though...