Metadyne Thumper - Issues and remedies

[Bow]

I have a custom piston in mine as well. Works fine. I'm always a bit hesitant to run it on any kind of HP though. I'm just worries about blowing the clippers valve. I think I've had it for 7-8 years now.

My new piston still shreds that first oring on the Pistons stem.

From what I understand the original pistons were made on a machine that was very slightly mis leveled. That's where the bending comes from.

There is no real remedy for that except for replacing it with an aftermarket custom one, maybe make it slightly beefier.

There's no really good remedy for fixing that oring either since the Oring is pushed into the body of the marker and catches that air transfer hole and shreds. My only thought would be using one of those expanding internal chamfering tools to try and smooth the hole out a bit, but that could mess with the position of the Oring an make a brick out of the body. Let alone I don't know how big the hole is and if they make one of those that small.

I'm happy to see some other people interested in the thumper though!

[Siress]

Typical method of preventing air transfer holes from shredding o-rings is to burr hone the primary bore. Further, do that before sending it out for electropolishing. This is all prior to anodizing. Hard to correct that if it wasn't done.

[Chrisrook1]

So, long time no post and reviving an old thread all in one. But, things are finally settling down for me after the world went crazy, and I’m hoping to revive some dead markers for play. My Thumper just up and quit in the middle of a game one day years ago. Played a few games on 12ie, was in the middle of another, had just fired 2 shots, pumped for the third, and the trigger pull did nothing. I let it warm up for a while thinking maybe the reg froze, but it has never worked since. So, now I’m going through a full rebuild on it, but for the life of me, I can’t remember what the Clippard part number is for the valve. So, that’s where I’m hoping the smart minds here can help out. Also, seems my detent rotted away and split in half at some point, so was hoping maybe someone knew a source, or had a schematic/drawing of one so that I could cut a new one. I’m hoping I can get this thing back in running order and on a field soon, it’s always been one of my favorite markers, so it’s a shame to see it sit in a box.

[RuleOfSines]

I think the detent is just a Tippmann 98 detent cut and glued into place. Valve is Clippard MAV-3C

[Chrisrook1]

Thanks for that! Hopefully it’s just a valve, but the regulator is gonna get a rebuild anyway. It’s weird, when you air it up, air goes into the marker, but it doesn’t fire. Seeing as how it was working when it stopped, my first thought is a blown valve. But, for all I know, there could be a blockage or something up with the regulator.

[RuleOfSines]

There is a weird scenario Thumpers can run into, where the reg actually locks up, without ever actually opening and letting air in. I only realized it by accident on one of mine when I aired it up with the side plug removed, air never even reached the internals. I made a tiny shim that went around the reg so it would not go quite as far forward to prevent it.

[Chrisrook1]

Good to know! Sounds a lot like what I’m going through, so I’ll have to take the reg out tonight and give it a look.

[ccaallmmaa84]

I wonder if this is whats going on with my Thumper. would you have a photo of what your talking aobut?
I would air up my Thumper pump and shoot but no fire.
https://youtube.com/shorts/VSvBG5TIQPE?feature=share

[JustMrLarz]

I purchased mine new when I lived a couple of miles from the Metadyne factory. Real nice guys! Mine still works, and gets used pretty regularly to the shock of more than a few. If I don’t put an external reg onto it, it will lock up every time. CO2 or HPA run pretty smoothly even. The Palmer 12g reg bucket saved a lot of hassle on 12g, and a cheap old CP inline for HPA. I do have an annoying hiss/leak from the rear section when cocked, but it seems minor. Annoying as hell, though. Hopefully one day I’ll figure out why it is doing that.

[JustMrLarz]

Stupid question: does anyone have a picture of how the ball detent is supposed to look when placed correctly in the detent holder? Mine broke a year ago and I have zero memory of how it was positioned in the holder/breech area. I made my replacement work, but it sure as heck isn’t right. My method is very sketchy, and I cannot find a schematic anywhere. Any help is appreciated.

[JustMrLarz]

I found the instruction video from Metadyne 11 years ago, but it only shows a detent. Not how it is mounted.
edit: tippmann detents are close, but not nearly the same as what we had in the thumper originally.

[lordgore66]

Here's the two types of detents used in the thumper. Slim style is glued to the underside. Thick style uses a Tippmann detent cut down to fit. You'd want the lowest part of the radius rearward. Then the finger is cut down to fit flush when fully pressed down.

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[JustMrLarz]

Thank you!! Mine came with the slim style, so now the hard part is finding a finger of proper length and radius to replace my old broken original.

[Kit]

I cut up a fat oring for mines.

[Siress]

Every design quirk I learn about this gun is stranger than the last.

[XEMON]

After working on mine a few times and seeing some of the others, it feels like a prototype more than anything else ...
If you get one, think of it like you're getting a prototype that have issues and quirks unique to this gun with parts that are all proprietary and may or may not match the next one ...

[lordgore66]

Designed and 3d printed some replacement detents. mine fell apart getting back together. uploaded and free to use. https://www.printables.com/model/421...v1-ball-detent

[JustMrLarz]

Now *THAT* is going to be very useful. Outstanding!

[super squirrel]

hey guys while I cant help with fixing the old thumpers Metadyne has finally redesigned it. has all the same features without the failures. https://youtu.be/OIqxEgaLHDc while this video is just the first to come you can see the new marker sitting behind the guy in the yellow shirt

[Jonnydread]

Very interesting! Thank you for sharing.

[Chuck E Ducky]

So cool I would love an updated version of the thumper with all the kinks worked out. Hope they keep the stick feed and offer them in cool finishes.

[Hellion360]

Interesting, my thumper shot awesome for like three days before imploding. It was a lot of fun.