Lube tune on S1K

[Rixtrix]

After putting the new/used stock spring in the Shadow and lubing it up with one of Rich's kits, I put about 50 shots through it. Shrink tubed the guide and tophat, polished both ends of the spring, put a thrust washer between the tophat and piston and lubed it following the instructions that came with the kit, plus what CDT had posted about the shrink tube. Still twangs as bad as before. No foam in the stock, yet( do ya just put it in the back, or in the holes under the action, too?). Will it take some more time to quiet, or do I have to put more tar on the spring? Have most of the lube kit stuff left. Gonna try to take it to Airguns of Arizona on Thursday to see if they can chrony it before I do anything else, though.

Ric G

[Mikmark]

I did the shrink tube and lube tune on two of my Gamo S1ks with good success.  The third one I tried had the same results as yours....very twangy.  I ended up machining new guides and tophat that fit the spring better, which made for a successful tune.

[Rixtrix]

Even with the shrink tube on the guide and tophat, there was still a lot of clearance between them and the spring.  I have some thicker tube than the Ace Hdwe. stuff I used, but don't know if it's polyolefin. Might try that,,,or the other spring I got from Rich,,,, or put some more tar on the spring at the rear guide area.
Back to the Shop!

Ric G

[Rixtrix]

I think this should be on the Airgun Mods and Tunes Forum. Sorry, never went there before.

Ric G

[CharlieDaTuna]

Hey Ric...the thrust washer does go between the tophat and the piston. Adding more lube will not really solve the problem either... at least for long. That being said, I wonder why the spring and guide are so loose with the shrink on it. On most of the later Gamo's, they necked down the guide considerably and you may want to add a second layer. I've never played with the heat shrink on the later guides and would think that is the problem. Anyhow, gonna send you a PM.

Hey...sent you an e-mail instead.

[CharlieDaTuna]

If you use a polished stainless steel thrust washer between the tophat and piston, that should be enough. You already have the spring polished on both end so there should be little resistance on the spring seats. Adding a thrust washer either or both ends of the spring won't hurt but you will gain little if anything in the reduction of torque and improving cocking. All it will do is add a bit of preload on the spring.

[CharlieDaTuna]

Did you get that figured out?  After I talked to you on the phone I checked again. The stock Gamo spring should have an i.d. of about .523 to .525.

[Rixtrix]

Thanks for the info, Bob Had to work late tonight and forgot to bring my caliper home. Will check it out tomorrow night after work. Still have the broken spring to compare, plus the other spring I got from Rich.

Ric

[Rixtrix]

Took the S1K to AOA to chrony it today. Shot 853 fps with CPL's (7.9 grain) and 835 fps with Daystate FT's (JSB Exact 8.4 grain). They really liked the GRT-lll trigger there. The Shadow's really a low-end gun compared to what they carry, but they're a nice bunch there. Picked up a tin of JSB Predators now that I know the gun is up to speed.
Whoops, time to go try it out.....................................

Ric G