Tuning Need help with FWB 601

[CCHASTAIN]

Received my long awaited package from The Netherlands today . Seem to have received a couple of scratches during shipping but other than that it looks really nice . My greatest problem is when I shot it it sounded very weak and when I pulled out the handle to cock it made the sound of another shot . Chrono'ed it and got around 275fps . It seems to me as though the valve is not releasing all the air from the chamber when firing. Any ideas ? 

Chris

 

[Lewis]

Following with interest. I have a 600 that occasionally will "pop" part way through cocking and not compress air. Opening all the way and cocking again works. Not sure if these issues may be related.

 

[CCHASTAIN]

After a web search I found this is probably a common problem with the 601 . Seems to be a bad valve seal most of the time . I guess I will try resealing first if I can find a seal kit .

 

[pearl]

Nikkonos on ebay. He has parts in stock. Neal Stepp with International Shooter Service and maybe Pilkguns. I have purchased from all 3. 

 

[CCHASTAIN]

Appreciate the info on where to buy seals . I disassembled the rifle and it definitely has a bad valve seal . 

 

[Arzrover]

My 600 failed to hold air recently so I spent several hours making the seal on the left, trying it, taking it back apart to modify, etc.The original is in the center. I made that left one from a sheet of 80 D polyurethane. Apparently that is too soft or really needs that depression you can see on the other 2. It would hold air but barely spit the pellets out. I ended up ordering the white one (factory replacement) and I'm happy to say it spits them out with authority now. Haven't chrono'd but makes clean holes in the paper and not a lot of holdover for 30 yds, so good enough for me.

They are pretty easy to replace, so don't hesitate to take it on.

Bob

 

[Aeromat209]

My newly acquired 602 after 20 shots was doing the same thing .A pop when cocking the lever and the shot was more of a thunk at lower FPS . My chrono starts at 600 FPS so not sure on the slower speed. My 602 is also able to shoot bypassing the cocking arm compression but with this malfunction would actually release compressed air on the practice first shot . My seller said it sounds like an "Exhaust valve seal " I bought a reseal cocking arm seal kit from Nikkonos on ebay . Got the parts but after watching the Austrian/German English sake Youtube I decided it was a bridge too far for me . My seller is going to complete the repair for me and I am happy with this outcome!

 

[CCHASTAIN]

Received my seal kit today . Replaced the valve seal only so I would know if that was my problem . Problem solved ! Shoot's consistently 566-569 fps . Aeromat 209 I don't know if the 602 is the same or not but it was a very simple job . Now I have to choose between the 601 and my 2002 , gonna keep one and buy a PCP . Thanks for all your replies .

Chris