Hey guys, working on a B2K. I replaced all the orings and lubed it accordingly. When I gas it up the bolt stays in the forward position and doesn’t cock back. HPR input pressure is at 250psi. LPR is screwed in until it leaks and then screwed out a half turn. Solenoid clicks when trigger is pulled. No leaks from anywhere. Any idears what to look at next? Somewhat familiar with these but not super familiar. Haven’t come across this before. Thanks!
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What year is it? Photos are your friend. Clean and lube the noid first. If you already did that there is a chance you put it back together wrong.
Where does it leak from when the LPR is over pressurized? That could be a clue as well.
Are all the air passages clear? I had a MacDev that had a massive chunk of "o" ring stuck in the tiny air passage once that caused a lot of headaches.
I suspect this one is a good candidate for LPR porting. Back the entire LPR out 1/4-1/2 turn and see what it does.
If you keep going in on the LPR, does it eventually recock and does the leak get worse? Does it never recock?
Report back and we will go from there! -
Thank you sir! I’m not exactly sure what year it is but I attached a photo of it as it sits.
I didn’t touch the noid the first go round but just took it apart and cleaned it, lubed it, and put it back together. Didn’t find any chunks of anything during that process. No change afterword.
The noid leaks out of the little cut out where I’m pointing to when I turn up the lpr. The leak gets worse the higher I go but it never cocks. It has yet to cock since I started working on it for a friend.
I unscrewed the lpr housing a quarter and then a half turn, no change.
Thanks again for your help!Attached FilesComment
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Ohhhh that's a sexy X-Mill. Never actually owned that style but always thought they were hot.
Based on the OG trigger frame I'm thinking 02 at the latest. The 03 the frames got wayyy better and the 03.5/4 frames were perfection. It's a 3/32 dowel to fix the trigger slop on the OG frames or the 03 frames.
Back to the issue at hand.
That's "the bitch" hole.
It was initially designed as a pressure relief to protect the noid from damage, but realistically there are a bunch of things that can cause it to leak though, not just LPR failure.
Fresh manifold "o" rings?
Are you sure the noid is attached securely to the manifold? Shit needs to be tight but not too tight or you will strip out the manifold. Use a little finesse and wizardry.
Did you rebuild the ram?
Ram leaks will manifest out of that hole.... unfortunately the best way to determine a bad ram is with an LPR guage or part swapping with another functional B2K. Rams are more or less unchanged with only minor details across all generations.
Break out a lighter, rebuild and polish the ram, and report back.
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Good evening, made a little progress, but not that much. Took out the ram, heated ‘er up, replaced the oring inside, polished, and put it back together. Made sure the manifold and noid were tight as a tiger, and gassed it up.
At first nothing happened. The lpr was about flush with the housing and I started to turn it in/clockwise. Noid started leaking again through that little channel I pointed at, but I screwed it in some more and the leak stopped and the bolt pushed back. Successfully fired one shot, and now the bolt is forward again and won’t go back. Turning the lpr from flush to all the way in will leak through that channel but the bolt stays forward.
Not sure if I’m missing anything or if there’s anything else to try?
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After a second look at the diagram on ICD’s website I replaced the oring on the ram shaft but looks like there’s one inside the front of the ram housing that I missed. I’ll have to open it up again and try again.Comment
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Hey now, yes I took apart the lpr, changed the oring on the piston, and lubed.
Took the ram apart and replaced the oring in the ram housing I missed the first time.
So now when I increase the lpr pressure from zero it will leak from the drivers side passage under the noid and then eventually seals.
Bolt doesn’t move back at all. It’s currently on the full auto setting and when I hold the trigger a little air puffs out of the rear passage and drivers side passage under the noid with each shot. As I increase lpr pressure the bolt with start moving ever so slightly and little chuffs of air come out the barrel. Eventually with more pressure it leaks pretty bad from the two channels and the air coming out of the barrel stops. Feels like it’s trying to do its thing but with the leaking air around the solenoid it can’t build enough pressure.
Could it be the gasket under the noid? It doesn’t look bad and isn’t torn, but it is approx 22 years old. Everything parts wise are in good shape and now every oring in the gun, as far as I can tell, has been replaced.
Thanks again guys!
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Everyone always "thinks" it's the gasket under the noid, but I have never once see that gasket ever actually fail on 20+ rebuilds. Its most likely your LPR, it's a known problem area with these in the first place.
Are there any cracks in the noid? That or a blown "o" ring are the only things that really fail....
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Gotcha gotcha, no cracks in the noid that I can see. I’m holding out hope since it did cock that one time. I’ll have to break it all down again, relube, and try it again. I appreciate the help!Comment
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Edited my original reply... I glossed over the fact that you said it was not cocking when gassed up. When it's gassed up, can you manually cycle the bolt back? ie, is there pressure holding the ram forward, or is there simply no pressure going to the ram to move it back? And what happens when you press the button on solenoid to move the solenoid valve manually?Last edited by RichM; 08-06-2025, 04:31 PM.Comment
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Hey guys, I got it working. I cleaned, lubed, and reassembled the lpr again. I saw an old PB Nation post about how if the black back cap of the noid, although it looks identical on both ends, it matters which side is up and which side is down. I had taken it off when I was inspecting/cleaning the noid. I flipped that around, gassed it up, and after a couple turns of the lpr everything functions and there are no leaks. I’m guessing it was that noid cap that made the difference more than another lpr service. Thank you all again for your advice along the way!Comment
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Hey guys, I’m back (sorry). Any tips on getting the fps up to 280? Lpr is stock, Air America Messiah hpr that was just rebuilt. I think I’ve tried every pressure combination between the lpr and hpr and a light autococker valve spring instead of the stock valve spring. Hpr pressure between 200-300 it’s in the 225 fps range. Up in the 380-420 range (which I think is too high) I’m in the 260-270 range.
Lpr is screwed in until it starts to leak from the noid and then backed out half a turn. I can turn it up a little without leaking but the shots get significantly louder/sloppy sounding and nothing changes as far as fps go. When I turn it back down a little it goes back to the quieter/smoother/tighter feel.
The only thing I have to compare it to is my BKO with stock everything and it’s shooting 280 at 300 psi.
Thanks so much again!Comment
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What barrel are you running? What size is the paint? B2ks like a tight fit...0.685 at the max.
I really want to emphasize how good the SLPS autococker valve springs are in these. Wayyyy lighter then even "light" autococker springs. SLPS is the way to go if you haven't already.
What size is the air transfer on the kapp vert ASA? I've never managed to have my hands on one, but moving from 3/16 to 1/4 is usually good for 15-20 fps at any given pressure range. A drill press is your best friend. Failing that it can be done with a fresh bit and a cordless if you are careful and know what you are doing....
Does you bolt have the three "o" rings and a ramp? superman has volunteered to start adding "o" rings and the top ramp to the bolts since BMC is temporary still out of action.
If all of that fails, move to a higher volume reg. Regs are not all created equal, AKA, PPS, and MacDev Gladiators add extra volume up top, and it's shockingly noticeable the impact it has on these guns.
If your ram is poorly polished that can have an impact too. I've noticed lately that the brand of "o" rings used to rebuild the as can have a large impact. Usually "o" rings from ACE hardware work best. I'm not sure why, but other kits seem to be too tight.
Let me know if it's still not working after that.
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Good morning, I polished the ram and that got me to the 275 fps range which is good enough for me. Thanks for this tip! Not sure why I didn’t do that the first time I had it apart.
Barrel is an OG 689 CP barrel. My left over field paint is in the 679 area so I’ll probably pick up a cocker to icd adaptor to run a freak barrel.
Not sure what bolt is in this, but it’s delrin with no orings, I attached a picture.
Thanks again for your help!Attached FilesComment
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