Tuning How to adjust Daisey 747 piston?

[caito222]

I have had a 747 for 5 years now and finally read the instructions. Adjusting the trigger from 4# to 2 # really helps. Wish i could get it a little smoother. 


The gun shoots well but I wanted to adjust the piston due to age and number of rounds thru it . I has no leaks. I have not had it on a choronograph.
To adjust the piston the directions state after firing, cycle the cocking handle and note when resistance is felt when closing the handle ideally 1 1/8-1 1/2 inches from the closed postion.

When I try to do this there is absolutely no resistance. If I turn the gun horizontal the cocking handle would fall open and back against the body of the pistol.Am I missing a step? After firing and before opening the breech the charging handle moves freely.

Even thought it is holding air, shooting ok, should I assume it needs the seals rebuilt?? Am I doing something wrong? If I replace seals should I replace the valve ? Lots of seal kits available. Am I foolish not to buy a kit now while they are available? PS I did lubricate the piston with airgun oil

thank you











Am I doing something wrong?PS I did lubricate it.

 

[Ripper]

The only thing I can think of is maybe it is just way out of adjustment and not showing any resistance. I just rebuild a 717 and had to adjust my cocking arm.After I rebuild it my cocking arm was only about a half inch away From the side of the gun.So I adjusted it to where it was just a little under 1 1/2 inches. That’s why I’m thinking that maybe if it is way out of adjustment it’s not going to show any resistance. 

 

[Ripper]

I also wanted to say that I don’t think those seal kits are going to run out anytime soon because I found several people that were selling them and those pistols are popular.And also, those valves that they supply with the kit are different and do not work. I had do use my original valve which was still in good shape.

 

[caito222]

UPDATE

I dragged out my chronograph which has not seen the light of day for years. 7gr pellets 270, 8.2 gr pellets 225fps

So looks like I will order a o-ring kit. Any ideas on how to improve the trigger maybe get it a lighter. I have adjusted it but it is pretty rough. thanks

 

[Odoyle]

The trigger parts are made of potmetal like zinc. If you try to overdo it you may eventually wear out to a point it may be in an unsafe situation or just quit firing. Order lotsa extra parts first just in case if they are still available.

I'd run Alphabet org auto trans stop leak quick fix everywhere b4 attempting a rebuild.

The slack adjustment is a gear like take up you see when pump is extended you use a screwdriver to turn it.

 

[John "spysir" Blount]

Have you looked at : https://anotherairgunblog.blogspot.com/search/label/Daisy%20747 ?

Not even 100% sure JG still is but hopefully https://www.jgairguns.biz/747-c-78_186_672/



Give us an update when it's healthy again.



John