634 tune guide

[LAalex]

Anyone aware of a tune guide for these guns?  Any hints or no-no's when taking it down? I love the rifle but it is a little buzzy and would like to smooth it up inside.  Thanks.

Scotty

[LAalex]

Found this in an earlier post by chuckinohio:
 .https://sites.google.com/site/cherrytwist/slavia631tune-up

Scotty

[Slavia]

I have a 631, which is nearly identical.  I polished the spring ends, seats, and spring guide.  I lightly honed and deburred the trigger parts with a whetstone.  The muzzle crown got the brass screw treatment.  It was not un-lubricated as some have reported, but the factory grease was hard and dry.  I reassembled with ordinary hardware store 1% moly EP grease, and the buzz went away.  It has been 10 years, and it is still going strong.  The spring guide is stamped sheet metal with an open seam down the length.  I have read that the guide diameter can be fitted to the spring by prying open that seam, but mine didn't need it.

If you don't already have an exploded parts diagram, a Google search will find one in short order.  As with many guns, the action comes out of the stock with three screws.  There is a leaf spring that nestles in the wood and wipes against the cocking linkage.  Be sure to find that before it drops out on its own and gets lost.  The end cap holding in the spring is threaded (no transverse pin).  Mine is so long that the spring preload is completely relaxed before you run out of threads, so no spring compressor is necessary.  The 634 in the link below looks to be the same.

The trigger parts must be removed to unscrew the end cap.  It's a pretty simple design, with only two pins that need to be pushed out.  The trigger has two springs.  One, a leaf spring, mounts on the trigger guard.  The other is a tiny  coil spring up inside.  Take photos or make a sketch so you can get it back together.

Here is a You Tube video about disassembling the 634.  Unfortunately, it's not in English, but it's easy to see what the guy is doing:


Here is the assembly video, by the same author:


The trigger guard is plastic, so don't over torque the stock screw or it will crack.  In my photo you will notice an aluminum trigger guard for exactly that reason.

The front sight sits in a dovetail, with room for extra movement.  I found that the position of the sight (and now muzzle brake) makes a difference in accuracy.  I shot groups and moved the sight at 0.050" increments until I found the sweet spot. 

The barrel pivot screw should be adjusted just tight enough so that the barrel of the cocked gun will stay put at any point of its arc.  There is a keeper screw to lock it in place.

[LAalex]

Thanks Slavia.  I will use those videos when I open her up.  I noticed for a short while these were $132 on WM.  These little rifles are really sweet for the $$.

Scotty

[Slavia]

I agree.  The 631 is a little anemic for outside, but inside at 10m it will dump pellets into a pencil diameter hole all day long.  The American market is all about power, so it was a great gun in the wrong place.  Your 634 is more powerful, but probably came too late to make CZ an airgun star over here.

My trigger guard cracked, and CZ USA told me it would take 6-9 months for a replacement to get here from the Czech Republic.  I said nuts to that, and made my own from aluminum.  Same with the little knob on the barrel release.  I have my trigger set up so the adjustable spring doesn't contact the trigger blade until just before release.  It has a two-stage "feel" without altering sear engagement, and is quite manageable.  Other than those two parts, the gun is all wood and metal.  It should last a good long while.

The gun has no anti-beartrap mechanism, so it can be carefully de-cocked.  It also means that if you should accidentally thumb the safety off and press the trigger, the barrel will snap shut.  It's a good practice on any springer to keep one hand on the cocking lever while loading.

Have fun with it.

[chuckinohio]

  The 631 and 634 are darn near identical internally, and a tear down guide for one is good for the other as a tutorial to get you going.

[joek]

just ordered one from amazon for  $134, Has the fugly plastic stock that I'll swap out to my 630 or 631





https://www.czub.cz/zbrojovka/cz-spare-parts/Rozkres-cz-slavia-634-cs.pdf