What you need:
Tetra strike
Airtech 2000 pump
small (1.5-2") section of 5/16th" vinyl tubing.
epoxy
hot glue
To start with, open up your tetra strike. This was slightly non-trivial with the sealed pump cap, but that came off pretty easily with pipe cutters. The light green grip on the handle came off with a flathead screwdriver. Here's what the internals should look like.
Remove the pump/tank/barrel assembly. It isn't held on with anything so it'll just come out. Next, cut at these two points.
You won't need the pump, but you will want to keep the L-shaped piece.
Next, cut off you AT2k pump tube right where the yellow stock tubing meets the pump tube.
Insert the vinyl tubing into the 'L' piece. It's a tight fit, but you won't need to widen the hole in the L any.
Now fit the other end of the L over the stub coming out of the AT2k pump tube. This will require a tiny bit of sanding on the outside of the stub.
From here you can insert the other end of the tubing into the tank assembly . I don't have exact measurements for how long the tubing needs to be, so guess long and keep cutting a little bit off until it fits properly in the shell.
One thing of note: There is a little tab coming out of one side of the shell. This tab used to hold the pump in place, but now just gets in the way, so get rid of it. Sorry for the overexposure, but you should be able to see a white line near the center. This is where the tab used to be.
Now just epoxy all the joints to make it airtight, and reassemble. The green grip piece will just snap back on. You will want to use hot glue or something to hold the pump in place, but the rest of the tank assembly will stay put without any work. Make sure all the spacers on the firing pins are behind the trigger. You can see in the first picture, the third from the top is not right. You should also probably glue the AT2k pump cap on (don't forget to plug the pump first). I replaced the barrels with 4" of cpvc as well.
There you have it. I usually pump it 8-10 times. It could probably take more, but at 10 the trigger pull is already pretty hard. I usually end up firing the first two barrels at the same time since it takes too much force to pull the trigger, and I can't stop before the second is already fired.
