A problem I had when fist I had the rifle it went away, but now back with a vengeance. On bottle fitting, hammer back and locked down, the gun immediately expels the bottle air through the delivery valve. I am stumped as to why this is open, and is there a quick fix? Popping the hammer once or twice does nothing. It has dumped two bottle in quick succession. Thanks.
you want the bolt forward mate, with it back you have let the air go straight through to the barrel as there is no pressure on the valve stem.
There is a valve return spring the help close the Valve!
So when you screwing on a Full bottle. Have the Hammer cocked....
This is to make sure there is NO hammer pre-load pressure on the valve!!
The Bolt itself can be open or closed....
So if you have air rushing down the barrel...
It could be a Bent Valve-stem, blown O-ring on the Valve-body or maybe a little debris on the
Sealing surface of the valve-stem/valve-body.
So quick disassembly and inspection is needed..
Stuart
Yep, from your other issue of the inconsistency I'd go straight for a look at the valve, they're almost certainly linked.
the valve is behind the middle cap at the front of the block, & unfortunately there are several different types as well as poor quality copies off 'the bay'
It's easy to swap them, but Bob would be the easiest place to get one.
Probably still worth popping it out to take a look as it might be just an O ring, plenty of info in the tech data area.
The O ring guide has pics of the valve body & shaft (top middle & middle middle) it might be that someone wrongly fitted 2 rings to the valve shaft which can 'lock it'
Quote from: Ca_Varminter on June 11, 2023, 04:07:45 PMThere is a valve return spring the help close the Valve!
So when you screwing on a Full bottle. Have the Hammer cocked....
This is to make sure there is NO hammer pre-load pressure on the valve!!
The Bolt itself can be open or closed....
So if you have air rushing down the barrel...
It could be a Bent Valve-stem, blown O-ring on the Valve-body or maybe a little debris on the
Sealing surface of the valve-stem/valve-body.
So quick disassembly and inspection is needed..
Stuart
Thanks for that Stuart, its what I have been doing, but I did it again and it seemed to work, But, I feel sure there was the tinyest leak sound, and sure enough the bottle gas leaked away. So I will follow angrybears tip and pull the valve with that out we will see what will be revealed. cheers for now.
Quote from: angrybear on June 11, 2023, 07:05:41 PMYep, from your other issue of the inconsistency I'd go straight for a look at the valve, they're almost certainly linked.
the valve is behind the middle cap at the front of the block, & unfortunately there are several different types as well as poor quality copies off 'the bay'
It's easy to swap them, but Bob would be the easiest place to get one.
Probably still worth popping it out to take a look as it might be just an O ring, plenty of info in the tech data area.
The O ring guide has pics of the valve body & shaft (top middle & middle middle) it might be that someone wrongly fitted 2 rings to the valve shaft which can 'lock it'
Sound advice, I will pull the valve and see what lurks within, even with it out I can post images for further advice. cheers for now.
The story so far: Out with the valve components, and I might see exactly where my problem is (angrybear)!
Awaiting confirmation, until then just how do I get the valve head out? It wont shake out and I don't want to start poking anything in there.IMG_1025.jpeg
if you mean valve body removal remove side location screw then drop the hammer out,you will need to remove trigger to do this.then probe out from the rear with something like a pencil or chop stick.dont use anything metal
kevG
Do yourself a favour and ditch the bronze filter while you are there.
Put a spacer in the cap to delete it and do away with the issue of it breaking down and scattering glitter in your nice shiny new internal parts.
Mine has been running minus filter since the day I got it and no ill effects.
Kind Regards
Rhys
Sometimes dry-firing will pop it out, I use a bit of 1.4mm stainless wire bent at a right angle (4mm) to fit down through the valve & pull it out.
Actually it's a fishing weight grip wire (Gemini double D fixed grip wire) see pic, sorry I forgot to mention the locating screw in the side of the block, cheers Kev.
The bit that seals is the wide rim of the stem on the face of the head/body facing you in the block,
make sure the body face is clean & un damaged,
Try just taking off that middle O ring on the shaft & reassembling, it should allow the stem to run much freer, although as it's apart you may as well get an O ring kit from the bay (item 251412173829 a good seller) & a tube of silicone O ring grease if you don't already have some (item 353352160132)
Once Bob's back on his feet I'd replace the whole valve with one of his, & dump the bronze filter, but for that you need a longer spring & a cap with a smaller hole to support it, (top right of O-ring pic) I did the change on mine last year instant extra 2ftlb.
Rhys
Thank you well useful tip, and seconded by angry bear. Pieces of that in there are most unwelcome.
Kev G.
It is my intention to contact you in regards to this rifle. I will make that approach as soon as I get the present problems sorted. Thank you.
angry bear.
Good hints and tips, I will follow the replacement routes you have suggested. Things will have to go on hold until Dr Bob is Back in the swing of things, I will try fishing for that valve in the meantime. Thanks all.
just one more thing if you fire the valve out on a mk2 there is every chance you will jam the cocking bolt as hammer goes beyond design travel and jumps the trigger sear.if so just drop the trigger out to free things up what ever you do don't force the cocking handle.
kevG
A great tool to push out the Valve assembly....
A Chopstick!!
I knew being Chinese would come in handy!!!!
8) 8) 8) 8) 8)
Stuart
kevG
Decided I am capable of following your suggestion of trigger off, hammer out.
Just so I am clear here:
1.The bolt is left in? In what position? Hammer uncocked (obvious)!
2. The cover over hammer! Is that an adjuster, or a captive cover only? I own a chronograph so I am not in serious trouble to reset.Thanks.
if you mean the hammer end plug it can be adjusted to fine tune power.
the bolt probe is best left in the forward locked down position
kevG
Quote from: Dr Fox on June 13, 2023, 07:23:33 AMkevG
Decided I am capable of following your suggestion of trigger off, hammer out.
Just so I am clear here:
1.The bolt is left in? In what position? Hammer uncocked (obvious)!
2. The cover over hammer! Is that an adjuster, or a captive cover only? I own a chronograph so I am not in serious trouble to reset.Thanks.
If you are struggling i am in Llanelli, i can help you out if you need.
Kind Regards,
Rhys
Rhys
Thank you thats an offer I will accept if things start go go off. I am in Goodwick, so just down the road from you. Cheers Denis.
Looking closely at the valve stem, there is a notch in the stem end. Q. Is this a design feature or a fault?
it's just how it's made.should only realy have one oring at the rear though
kevG
Not a 'design feature' but should make no odds, that's just the face the hammer pip strikes, to knock the valve open,
the other end & the waist are the sealing & flowing areas.
The valve spring pushes the underside face of the stem rim against the valve body to form a seal,
on firing the hammer pip strikes the end of the stem pushing it forward, opening the valve, the air then flows past the waist out of the top of the valve body through the barrel port in to the bore & propels the pellet down the barrel, the spring meanwhile, rebounds pushing the stem back & again seals the valve closed.
When you remove that bronze filter it both, allows quicker airflow through the valve, & the volume of the metal is removed increasing the volume of air in the block pre-chamber.
Got thanks.
I followed KevG's advice and took off the trigger, and removed bolt. I know you suggested a hook pull out, but to be honest not even knowing what the item looked like, that to me was a risk. I have sent (or thought I had) an image of the component parts including the valve, find the site difficult to work with I am not sure He will receive the info.
In basic terms I am never comfortable with chopped unfinished springs, and there are two here. Also everything fitted dry as a bone. So if I repost all here perhaps kevG will see it. And yes the filter will go and I will fit a spacer to compensate for the spring fit.
That looks like a sub 12 long pip on the hammer rather than a short FAC one as well,
Lots of room for Kev to work his magic.
I always run with a dry lubed hammer, wet lube just attracts cr*p, but that's just dry.
its a standard mk2 fac pip. 9mm-ish
you don't just fit a spacer to make up for filter replacement, it's a disc with a tit on so the stem return spring as something to sit on and guide it true.you don't use the spring that you have now but a longer one,also you carnt use that valve body with out a filter.so to do it right you use a new valve and stem with return spring and disc guide.
kevG
Thank you. So, new valve, new spring, new stem, disc guide, and include a new end cap?.
Is DR Bob the suppliers of these, as e know he is unavailable at the moment.
Another point what about the two hammer springs coil cut and unfinished. Can I replace these?
SpringsIMG_1038 2.jpeg
you should not need double hammer spring even for fac,you can just heat the open coil end and shape to flat.what power is it doing.
kevG
This is exactly why I am seeking your expertise, previous history dubious, its even in a stock that its not fitted for!!
Chrono on one of the times I have had it shooting:
18.13 grn 925fps. 34.5ft lbs.
21.1 grn 880fps. 36.29ft lbs.
25.38grn 809fps. 36.89ft lbs.
Thank you. Denis.
PS. The damn thing is addictive, I want it the best it can be.