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Old 06-07-2012, 10:02 PM   #1 (permalink)
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RT Classic Tech help

Hello all,

I'm new to mags... I'd always wanted an RT, and recently picked up a clean, but "needing mechanical TLC" RT Classic.

I've been reading what I can find, but since it's kind of an odd beast, not sharing many parts with the other style valve, I'm having trouble diagnosing. I'll leave some notes here in this thread in hopes someone can lead me in the right direction.

I'm not at all afraid to tear into the gun, in fact I've had it far enough apart to replace all the o-rings already, though I haven't gotten a rebuild kit yet, so if there's something you think I should go check, just let me know and I'll get there and take some pics if it helps.

The current state/symptoms as best as I can describe:
  • When I air up the gun, it seems to set the sear just fine, trigger has approximately 1/16" free play, though I had to shorten the rod a bit, it had NO play at all when I got the gun
  • Usually when I air it up, the first few shots sound good, and it will even RT for 5-10 rounds maybe, and then it seems to just "puke".... bolt moves but very little air pressure coming out of the barrel, and sometimes it won't reset the sear after one of those "halfass" cycles.
  • The above performance is achieved only with the velocity adjuster cranked all the way in, where I do not get any air leak out the back like I would expect according to the manual. If i degas the gun and re-air it up, I can sometimes get a bit of leaking out the rear, but it usually quits pretty quickly. Again this whole time I only occasionally can get it to fire where it feels like it's pushing enough air to actually fire a paintball out the barrel.

The one variable I can't tell you at the moment, and for all I know could be 100% of my problems at this point... I am not sure what output pressure my tank is. It's a Pure Energy 50/4500, which I'm pretty sure is preset to 850psi...I know it's not really a high end reg on there, is it possible i need to just try a Ninja SHP or something or should the Pure Energy be sufficient, even if not ideal.
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Old 06-07-2012, 10:45 PM   #2 (permalink)
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Mark the hole on your banjo bolt in back and make sure the hole is lining up, if not shim it. Spider! used some ninja reg shim's. I used about 8 angel shim's, there super thin. Make sure the piece on the end of the power tube us on tight, the one that can be removed with a quarter. There a load of fun when you get em going. There is a good vid on youtube about how to replace all the o-rings. My Ninja tank is putting out 850 and the RT is pretty reactive for me.
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Old 06-07-2012, 11:20 PM   #3 (permalink)
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Honk, thanks for that tip, that didn't occur to me, but makes perfect sense. I'll find some shims (i love my local Ace Hardware ) and see if that helps.

Speaking of the power tube, i noticed that my RT has a "brass-colored" spring in between the power tube and the o-ring at the bottom, instead of the .2xx spacers that I'm used to seeing in various threads discussing these valves, and even the manuals on AGD's website all show spacers there, none of the diagrams I saw showed a spring there. Is that a problem, or do I just have an especially odd gun?

I did notice that when I set the bolt on the valve, and let it drop down til it rests naturally, there is a fair bit of play in the urethane washer still....the bold doesn't sit snugly against it. Given my limited understanding of how these guns work, that makes me think it's sitting on the o-ring at the bottom of the tube and needs more spacing (my other theory behind why i might need the brass spacers for the power tube).

Again, I can take pictures if any of this stuff needs clarification. Thanks again for the help
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Old 06-07-2012, 11:37 PM   #4 (permalink)
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OH! A bit of light.... I just saw a reference to that spring in the troubleshooting sticky in this forum... Looks like it came from the Level 7 kit. Answers that mystery at least Sorry for failing at research
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Old 06-07-2012, 11:55 PM   #5 (permalink)
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If it's not leaking, leave the power tube alone for now. The bronze spring is just the original spacer for the level seven bolt; it may wear out eventually and you can replace it with another or a spacer.

Don't tempt fate by making your velocity adjuster vent on over pressure.

First, did you give it oil when you had it apart? Four drops in the ASA is a fair start, or two or three in the banjo bolt port.

You need about 1000 psi on a bottle gauge at least to really debug a mag. You might try borrowing a bottle if you don't have a gauge on an ASA that will tell you what yours does. Old bottle regs can be farty as much and any other.

At the moment, you should probably order an RT rebuild kit from airgundesignsusa.com, since tunamart is a bit occupied. I think they still have RT kits(?). yeah,

RT O-Ring Replacement Kit

Old urethane o-rings can get hard instead of mushy, making them bind up instead of leak, so if any of them looked dark or hard, you might just as well rebuild it.

Also, take the valve out and make sure the bolt (without the spring) drops though the body washer without a problem. While my RT was pretty clean, the body washer had a few years of corrosion/paint reside on it that sanded off relatively easily. Still, it needed to be sanded off.

If you're not leaking and you're RT'ing sometimes, you're not far off the mark.

***

If you haven't checked, the bolt spring should be at least 1/8" longer than the end of the bolt. 3/16" - 14" over is a fresh spring. Flush with the tip is getting into problems.
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Last edited by Spider!; 06-07-2012 at 11:58 PM.
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Old 06-08-2012, 01:20 PM   #6 (permalink)
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Ordered a rebuild kit for the RT this morning. The o-rings in there are definitely old. some of them are decidedly brown. That does lead me to another point, the on/off pin seemed very tight in the on/off valve with the current ancient o-rings. It seems to me that it shouldn't bind that much, right? Hopefully the new kit fixes everything and the gun is good to go soon. I've been playing almost every weekend this spring and it sucks to leave it behind
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Old 06-08-2012, 01:41 PM   #7 (permalink)
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Quote:
Originally Posted by Spider! View Post
First, did you give it oil when you had it apart? Four drops in the ASA is a fair start, or two or three in the banjo bolt port.
...
Old urethane o-rings can get hard instead of mushy, making them bind up instead of leak, so if any of them looked dark or hard, you might just as well rebuild it.
...
Also, take the valve out and make sure the bolt (without the spring) drops though the body washer without a problem. While my RT was pretty clean, the body washer had a few years of corrosion/paint reside on it that sanded off relatively easily. Still, it needed to be sanded off.
...
If you haven't checked, the bolt spring should be at least 1/8" longer than the end of the bolt. 3/16" - 14" over is a fresh spring. Flush with the tip is getting into problems.
Spider! Thanks for the walkthrough. I did give it some oil in the banjo bolt, mostly as it had been very slowly leaking from the banjo and i figured some oil might help it stop (which it did). As I just posted, I ordered a rebuild kit from AGD this morning. I only live about 15 minutes from their address in Cary, IL so hopefully I should have it pretty quickly. I wish I could have just taken the gun into them, but I emailed Roman and he said they don't take walk-ins

Also in my previous post I did notice a lot of the orings to be discolored brown, and the on/off orings caused significant binding on the on/off pin (which doesn't look modified or ground down at all, but I don't have a set of calipers to accurately measure it). So again, hopefully the rebuild should fix that. I'm assuming the on/off pin should float pretty freely in the valve?

I will check the body washer clearance tonight, thanks.

The bolt spring, while I haven't measured it exactly, I think is fine. It sticks about 1 coil off of the top of the bolt while sitting on the table. I'd say it's at least 1/4", possibly more.

Thanks again!

Last edited by BLSully; 06-08-2012 at 01:44 PM. Reason: left out some detail
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Old 06-08-2012, 02:29 PM   #8 (permalink)
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Yes, old o-rings in the on/off can bind it up. The pin should move with a smooth slide, but not freely; there's a little o-ring inside the on/off top that can cause trouble in it's old age. At some point, you just can't keep enough oil on it.
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Old 06-08-2012, 02:55 PM   #9 (permalink)
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That seems to be the one that was causing the most binding. it was tight enough I couldn't pull the on/off pin out of the valve, i had to push on the narrow end with a small allen key to get it out of the valve
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