GTA

Airguns by Make and Model => Benjamin Airguns => Topic started by: S.S.Tupperware on July 17, 2011, 10:30:42 AM

Title: Tuning NPXL?
Post by: S.S.Tupperware on July 17, 2011, 10:30:42 AM
Never tuned an AG, but from what I gather it isn't too complicated... I have a mg welder and a plasma, so wjippin a compressor together will be easy. Might go to Harbor Freight for some cheap clamps and doo dads. I have Breech bushings and the ram bushings ordered... gonna get a seal, lube, and a trigger next week. So any tips, videos, or any other basic knowledge you could provide to help this first time go smoothly. Thanks
Title: Re: Tuning NPXL?
Post by: josh3rd on July 17, 2011, 11:29:25 AM
Just take your time.  Make sure you do everything right the 1st time and you will never have to worry about it again.  Take pictures for personal reference. Make sure that when installing the trigger group after tuning it that you lift the sear up and over that little bridge at the end of the cocking slot. When applying moly, make sure it is just a thin coat.  you want to be able to see the metal.  Get a brake honing tool(320grit).  When using it, don't bring it up near the cocking slot because you will brake a stone or two.

josh
Title: Re: Tuning NPXL?
Post by: Jay on July 17, 2011, 12:10:08 PM
 Know also Conrad that the "XL" does not need the use of a compressor as the NP has very little if any preload on it, still you will be ahead of the game if you make one, as you are sure to get other AGs that will need one.
Title: Re: Tuning NPXL?
Post by: S.S.Tupperware on July 17, 2011, 12:38:24 PM
Good to know about the compressor. I will be cleanin out the phantom also in time, but it is shootin great right now, so besides the brass breach washers i am gonna leave well enough alone... Anyone have any tear down pics or vids? I imagine a cheap HF micro file kit along with my dremmel should get the job done... I have a brake hone here in one of the tool boxes somewhere. I guess get the moly with the seals...
Title: Re: Tuning NPXL?
Post by: Rickey on July 17, 2011, 06:53:29 PM
Jay if the XL doesn't need a compressor does the Trail?
Title: Re: Tuning NPXL?
Post by: gene_sc on July 17, 2011, 07:48:06 PM
I am not Jay but I will answer your question...:) Yes the Trails and Titan gas rams need a compressor to put together.:)
Title: Re: Tuning NPXL?
Post by: S.S.Tupperware on July 17, 2011, 07:51:31 PM
Well I have the trail Xl in .22 so i will need it?
Title: Re: Tuning NPXL?
Post by: Sniper808 on July 17, 2011, 08:42:43 PM
No you DO NOT need it for the trail xl
Title: Re: Tuning NPXL?
Post by: Jay on July 17, 2011, 08:56:51 PM
As Mr.Gene an Sniper said guy's, the XL no compressor needed, 99% of other AGs out there YES use a compressor, so always remember, Stay Safe, the springs an NPs can have alot of force behind them an will do some serious harm.
Title: Re: Tuning NPXL?
Post by: john on August 11, 2011, 01:50:50 AM
I finished my first ever home tune today on my first ever airgun...Trail NP (not XL).

A full fledged spring compressor was not needed as there was only about a half inch of preload on the gas ram so was able to get away with nothing more than a $13 24" barclamp from Home Depot. I had removed the barrel from the action so didn't need a longer clamp. The action is ~14in long.

Regarding deburring the inside edges of the compression tube, with careful manipulation using axial strokes of the 3-stone brake-cylinder hone, I was able to do alot of the deburring by hand. No seal damage was done upon reassembly. Used 3-in-1 to lube the walls and stones when honing...the stones soak it up like sponges so dowse 'em good. Used a drill of course to rotate the hone to scar up the front section (aka compression chamber) of the tube. Flushed with denatured alcohol.

Used a piece of sponge screwed to the end of a wooden dowel to swab moly onto the inner wall of the tube...STILL wound up with too much moly in there and it spooged out the transfer port when the piston was pushed in...oh well, after about 20shots, the smoke began to clear...place stinks now.::)

That new seal is a very tight fit going onto the front of the piston; i don't know what the trick is to make that easier. I spit on it but next time I will try isopropyl (makes synthetic stuff slippery). In spite of moly, the seal was also a tight fit going past those cylinder edges...but gently wiggling it helped...and that baby is unscarred, totally sanitary. At least there are no compression tube threads to deal with as the Trail end cap is retained by a pin and not threaded as in the case of the XL.

Time will tell if any benefits are gained. Fwiw, the edges of original seal weren't bad at all so I don't really expect much improvement. But wow a learning experience and alot better understanding of how this thing works. Next time will not be nearly so intimidating.

Oh, a not totally necessary tool, 'alignment punch', I picked up at Home Depot makes life easier when you have to line up holes...it's just a punch that's tapered.

Have fun.
Title: Re: Tuning NPXL?
Post by: bill/sjca on August 11, 2011, 04:11:16 AM
will honing oil cause dieseling?most will get cleaned up but is that an issue?
Title: Re: Tuning NPXL?
Post by: uncle paulie on August 11, 2011, 07:43:39 AM
1) Yes
2) maybe

Use the soda can trick from ezman604 to help get the seal back in or use some 400 grit wet or dry paper to take the top edge off the threads to reduce the possibility of damaging the seal when it goes back in.

http://www.gatewaytoairguns.org/GTA/index.php/topic,715.0.html (http://www.gatewaytoairguns.org/GTA/index.php/topic,715.0.html)

pv
Title: Re: Tuning NPXL?
Post by: Jay on August 11, 2011, 12:02:53 PM
Bill just use(while honing) or clean up the inside's after, with "hot" soapy water an ALL oil is a mute point.
Title: Re: Tuning NPXL?
Post by: Rickey on August 11, 2011, 06:00:18 PM
Gene, I don't understand.  Per crosman the Trail and the XL have the same configuration in the compression tube except the  XL has an adjust washer, part #6, that the Trail doesn't have.  Granted I've never been inside one and there might be something in there I'm not seeing but there doesn't seem to be a spring to compress like there is in my Shanghi Mod 61.  I'm just trying to work this out in my head before I get in there.  I read some where that there might be about 3/4 to 1/2 inch to push down in the reassembly.  Is this what your talking about using the compressor for? Rick