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Thread: RT Classic noob questions

  1. #1

    RT Classic noob questions

    I bought a used RT Classic around Christmas (with a tuned lvl 10 bolt) and I'm getting ready to take it out to play in May.

    I've put a little paint through it and it was (is) great...even got to experience the bolt NOT chop paint. Yay!

    That being said, I was sitting here yesterday screwing around dry-firing it and noticed a few things:

    1.) There's a "sweet spot" where the marker will cycle and shoot without leaking around the body/out the back on the banjo bolt. I drew a line with a sharpie to sort of tell where it is.
    2.) After "some" shots, the banjo bolt starts loosening, and when I look, sure enough, my line isn't lined up anymore.

    I tore down the marker and was looking at the rail and banjo bolt, and noticed that the line isn't perpendicular with the holes in the frame where the gas comes in. I drew a perpendicular line on the banjo bolt and put it all back together, lining up the *new* line, and the thing leaked like a siv and wouldn't cycle or fire. Tweak the banjo bolt a little so the "old" line is lined up, it works fine.

    Questions:

    1.) Does that sound right to anyone else? I'm having a hard time understanding why having the holes in the banjo bolt line up with the holes in the frame would cause this behavior, while having the banjo bolt tightened down so that the holes aren't exactly lined up works great.
    2.) Does the banjo bolt loosen on anyone else? If so, any suggestions on how to get it stay in place? I've seen threads about people using Ninja reg shims, but I thought that was more for helping with leaking than keeping it in place. I've debated using the "wrench-removable" loctite, but putting something like that inside my marker scares the hell out of me.

  2. #2
    Join Date
    Jan 2002
    Location
    southern IL
    Posts
    1,886
    I've never worried about the banjo being in a certain position. So far I've never had an issue in the past because of it. Only time it has e er vibrated loose unless I didn't have it tight to begin with.

    Right now my banjo leaks a hair. But that is because the o rings are literally 12 years old.

  3. #3
    Join Date
    Oct 2006
    Location
    Houston, TX
    Posts
    3,206
    The three rings on the banjo bolt contain the air between the rail and the valve. The two lower ones seal in the rail. There is only pressure internal to the banjo bolt between the middle and top o-rings (that section sees outside air pressure on the outside of the banjo bolt). The top o-ring seals against the valve.

    The trick to the whole design is to have the top seal in far enough (screwed in), without letting the middle o-ring come up out of the rail (not screwed in too far), all while anchoring the valve and body to the rail for some serious vibration. There are three tight tolerances in there, and the manufacturing of it all proved to be a bit much for the benefit.

    The RT valve design will not "do it's stuff" if the pressure is low. Your leak is lowering the pressure more than the flow restriction caused by having the ports unaligned. Instead of using a shim, people have used o-rings as spacers, which would be a little more lock-washer action.

    Make sure you use 90 duro urethane o-rings on the banjo bolt. They are stiffer and provide front-to-back alignment as well as some tension to keep the banjo bolt from turning on its own.

    If you have one of the older rails, it can be hard to keep it all set right. Tuna used to have the updated rail that doesn't leak easily. I recently updated my thread on sleeving the hole in the rail. That mod is still working after a year of fiddling with the level 10 and some play days.

    If it works in that spot, I would look for some sort of shim or spacer that will hold the banjo more firmly in the correct position.

  4. #4
    I will see what I can do! Thanks for the help, and the info!

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