Theoben Rapid Forum

Everything Technical About Rapid => Technical => Topic started by: Chris4658 on March 17, 2021, 09:12:37 PM

Title: Couple of leaks
Post by: Chris4658 on March 17, 2021, 09:12:37 PM
Ok guys, go easy on me. Probably not in the least bit 'technical' to 99.9% of you guys but we all gotta start somewhere hey?
After fitting one of Bobs brilliant qf kits today I used some leak detector to check for erm...leaks :) Whilst checking found a couple of non related leaks. Blanking plug on bottom of action is leaking, which again Bob has been great and is sorting out seal. Now he explained there's nothing hidden behind the cap that's going to go flying across the workshop when I take plug out, so all good there.
The other leak (which is very small, but want it sorted) is on the valve cap above the reg (if at all the rifle is regged??)
Now in basic terms, is there anything spring loaded behind cap? Is it just a case of discharging air/removing bottle, cycling and firing rifle to ensure no air in action, unscrew plug renew o-ring and nip back up? Oh, and it looks like reg needs to come off first in order to unscrew valve cap? Anything there to be weary of? Bear with me guys, my knowledge will improve with your help :)
Title: Re: Couple of leaks
Post by: Ca_Varminter on March 17, 2021, 09:40:52 PM
Well First make sure your Rapid is Fully Deflated.... No air pressure in reserve..
Yes will need to remove the Regulator.
The Blanking plug is were the Valve-Stem, Valve-body and return spring is housed.
The blanking Plus is und a little tension from the return spring.
So just go slow, it won't flying off....
here is a diagram of a MK I... but in general... it is almost the same!!
Just some of the parts look slightly different!
(https://photos.imageevent.com/scl_electronics/gun/air/websize/rapid-diagram3_1_.jpg)

So on that blanking plug, there is an O-ring..
(https://photos.imageevent.com/scl_electronics/gun/air/websize/valvespring-cover.jpg)
It may need to replaced.. or maybe just a bit dry and needs a little Molykote33

Stuart
Title: Re: Couple of leaks
Post by: Chris4658 on March 17, 2021, 10:01:50 PM
Thanks Stuart. Does the bolt have to be in a certain position/do I leave the bolt in the forward and down position after dry firing?
Thanks
Title: Re: Couple of leaks
Post by: Dr Bob on March 18, 2021, 12:47:06 AM
Told this was the place to be. 😇
Title: Re: Couple of leaks
Post by: Ca_Varminter on March 18, 2021, 01:22:28 AM
Quote from: Chris4658 on March 17, 2021, 10:01:50 PM
Thanks Stuart. Does the bolt have to be in a certain position/do I leave the bolt in the forward and down position after dry firing?
Thanks
Well if you don't have an anti-tamper plate.... I would pull the hammer-spring out... to lessen the hammer pressure on the valve..
But if you can't drop the hammer-spring out, I would lock down the bolt in the rear notch.
Also use a strong rubberband to keep the bolt in that rear notch, if you are not comfortable with it being there!

Good Luck,
Stuart
Title: Re: Couple of leaks
Post by: Chris4658 on March 18, 2021, 02:29:41 PM
Now sorted leaks thanks guys. Unbelievable fast delivery of o-rings off Bob, thanks fella!
There wasn't a huge amount of spring pressure when I took plug out, didn't delve any deeper, basically cleaned mating faces, stuck a new lightly molycoted o-ring on and happy days!
Now as I had to take reg housing off to get valve plug out, I was surprised not to find anything in there, does this mean I have a 'fast flow' rifle??
Title: Re: Couple of leaks
Post by: Ca_Varminter on March 18, 2021, 03:04:51 PM
Here is a Fast-Flow bottle adapter..
(https://photos.imageevent.com/scl_electronics/gun/air/websize/ff1.jpg)

Here is a Regulator Bottle Adapter..
(https://photos.imageevent.com/scl_electronics/gun/air/image.gif)

Most FAC are FF for higher power levels...
But there are Reg FAC , in .22 cal @ 40 ft-lbs

Stuart
Title: Re: Couple of leaks
Post by: Chris4658 on March 18, 2021, 03:28:53 PM
Thanks again Stuart, yeah, mine is defo the fastflow then.
So with knowing that, what is recommended fill pressure for this set up?
Last time I tested (before my chrono died) it was running 33ft/lbs. Have always stuck to 210bar, 4 magazines (48 shots) and refill. What pressure will power/trajectory noticeably drop off?
Title: Re: Couple of leaks
Post by: Ca_Varminter on March 18, 2021, 04:01:51 PM
Hi Chris,
Well now you are tedious side of Rapids.
The point you refill your Rapid is when you see a significant POI drop!
There will be of course a drop in Velocity...
This point is different in every Rapid.
It depends on the setup and porting!
So the best way is to test over a chronograph......
(https://photos.imageevent.com/scl_electronics/gun/ultimaterapid/websize/test1.jpg)

Good Luck,
Stuart

Title: Re: Couple of leaks
Post by: Chris4658 on March 18, 2021, 04:39:08 PM
So until I can get a new combro (sold out everywhere) unless you guys can suggest something else for same price, I'll stick to the the four mags and refill.
Thankyou for your help.
Title: Re: Couple of leaks
Post by: Ca_Varminter on March 18, 2021, 05:13:00 PM
Well a Chronograph will give you hard and fast data on your Rapid Performance.
But shooting target will get you give good feedback too!!
But Like I said above.
When the POI(Point of Impact), starts to drop to a where you
are not Happy..... Time to Re-inflate your Rapid!!!!

Have Fun!
Stuart