Theoben Rapid Forum

Airguns => Anything Airgun => Topic started by: jbe on October 28, 2025, 09:19:52 PM

Title: mk2 regulator needs some help
Post by: jbe on October 28, 2025, 09:19:52 PM
Evening, after some help with leaking regulator on my mk2 (leaks out of small hole on reg , closest to block as soon as bottle wound on). Understand they need calibration after new seals, both of which i cannot do. Any help appreciated, thank you
Title: Re: mk2 regulator needs some help
Post by: angrybear on October 29, 2025, 12:58:58 PM
In the tech section is an O ring guide which tells you the 2 seals to change BS803 & 005.
the large O ring on the reg is a spacer not a seal, Provided you have not yet messed with it you should be OK
as per the pic below, do not touch the blue nut, mark the knurled brass above the red O ring and the silver reg body so they align, now unscrew the reg body from the housing counting the number of turns, change the 2 small O rings, and refit the body counting the turns in, this sets the gap at the bottle seal green.
This should set the reg as it was, but run it over the chrono to check, (if you don't have access to a chrono buy one, every air gunner needs one)
Title: Re: mk2 regulator needs some help
Post by: jbe on October 29, 2025, 09:45:06 PM
Thanks for your help, i reckon i could do that. Ive got an  fx chrono to test with. Assumed it was alot more complex. Do appreciate your detailed explanation, regards
Title: Re: mk2 regulator needs some help
Post by: angrybear on October 31, 2025, 01:59:46 AM
No, doing those O rings is the simple bit, if you undo the nut to change the belvile washers, that's when you really need a reg tester, although you can do it without, by chronoing - adjusting the nut, re chronoing etc
Title: Re: mk2 regulator needs some help
Post by: jbe on November 25, 2025, 10:54:15 PM
Many thanks angrybear. All fixed. Appreciate your knowledge, regards
Title: Re: mk2 regulator needs some help
Post by: Bigal. on May 28, 2026, 07:46:15 AM
Aswell, working off the great info given, on the marked holding collar u can adjust the psi a thou up down.
Turn in a thou in, less core travel, eg less psi/fps in.
Out off the mark again u gain a thou up on psi/fps, Al