Air Arms Owners Club

My 2006 S400 developed a leak a couple of months back. Got a full service kit off Julian, any tips before I start please ?

Empty the air Dave

BBF

Take photographs as you go. It makes it easier to see where te bits go back
Kevin

Blackbaronfish wrote:Empty the air Dave

BBF

Good idea Ray

Outandabout wrote:Take photographs as you go. It makes it easier to see where te bits go back
Kevin

Yes, I may have thought of that once the gun was in bits Cheers mate, good tip

Hi,

...and yes. As it's 10 years old and possibly not been touched before I would change the exhaust valve while you are there. This should give you a flatter power curve and hence more usable shots in the sweet spot. Google 'exhaust valve extrusion' for an explanation from a chap called 'cloverleaf' (I think it's the first search result). Made a hell of a difference to my own when I changed it. Also give the hammer rail a good polish with autosol or similar and clean/degrease the hammer bushes. Run the hammer dry or if you must only the smallest smear of light sewing machine type oil. Don't use normal mineral based oils in any part of the rifle that is under pressure as you may experience how a diesel engine works . Use a silicon type one instead .. Abbey Silicon Gun Grease for example. Make sure you get the right O-rings for the gauge dog-leg (one is very thin) else you gauge may not work afterwards, trust me I know about that one . My guess is that it's the dog-leg that is leaking! Sparing grease on the hammer spring also.

Take your time and give yourself a bit of space and you will be fine. You have no anti-tamper to remove so the job is pretty straight forward and they are pretty simple to maintain. Don't forget to chronograph afterwards at about 130 bar with a heavyish pellet as they tend to produce the most power (my rifles really like JSB Heavies if it's a .177).

Most of all enjoy. It's a great learning experience and you will gain a lot from it i'm sure.

Mark

Here you go Dave.
https://www.youtube.com/watch?v=hytZ_LFUg3M

BBF

I managed to duck out of spending most of the day (and night) with my girlfriend's family, ahhhh relax. Anyway, finally with some time to myself I decided to set to work and give my S400 a full service. It developed a leak a couple of months back, so got a full service kit off Julian Bond, including a new exhaust valve.

The gun is a 2006 model and as far as I'm aware had never had a service. So out with the tools, I had never totally opened up a pcp before, but I must say it was relatively painless. Changed everything, bar the breech seal, which looks a pig to do, it OK anyway, so will leave for now. Just filled the gun, having a well earned cuppa, then out with the chrono to do a full test. Hopefully happy days

Edit: just had a chrono session. Before the service I was filling the 400 to 160, now I'm having to fill to 180. It's running right up there it has the little you know what screw all the way in and the firing pot set at 57mm. . idea's please chaps

Are you sure the venturi screw is all the way in as this would shut off pretty much all the air going to shove the pellet up the barrel. The screw on the outside of the rifle (at an angle) is just a protective cap. The venturi adjustment is a tiny grub screw underneath this cap.

Mark112 wrote:Are you sure the venturi screw is all the way in as this would shut off pretty much all the air going to shove the pellet up the barrel. The screw on the outside of the rifle (at an angle) is just a protective cap. The venturi adjustment is a tiny grub screw underneath this cap.

Yes I'm aware of this Cheers. However enough air and then some is still getting through.