Author Topic: Yugo Gas System Fix  (Read 86153 times)

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Tow4

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Yugo Gas System Fix
« on: October 24, 2005, 11:24:43 AM »
Hi all, I have been visiting this site for a long time and have found a lot of good information and very helpful members. I usually find the answer to my questions in here some place. I just registered because I finally have something to contribute.

I have two Yugo SKSs. One is in very good condition and shoots very well. The second one bought from a different source was in a very used condition. Cosmetically it is good, but has a lot of wear on the rifling and had a failure to cycle function problem. The gas valve was severely eroded. The gas piston and gas cylinder was pretty close dimensionally to my other SKS so I swapped the gas valve and that seemed to fix the problem. It would still fail to function once in a while but so did the good SKS.

I ordered a gas valve from Heddonpal. The valve I received was in much better condition than the worn out valve, but not as good as the valve in my good SKS. Now the action would cycle enough to stovepipe.

I figured that any replacement part I bought would be used so I decided I needed to find a way to fix it myself. I've read about the ball bearing flair mod but didn't have a ball bearing the right size. Most of the other options (machine a new gas valve) would cost more than the gun did in the first place.

After noodling the problem, I came to the conclusion that I needed a sealing ring. I took a regular paper clip and bent it around a drill bit slightly smaller in diameter than the countersink in the end of the gas cylinder and cut roughly to size. Then I put it in the countersunk area at the end of the gas cylinder.




I had a pretty large gap but thought I would try it anyway. (Sorry for the focus, I was hand holding the camera). It functioned flawlessly. I shot about 20 rounds to make sure and then went back the shop to make one with a smaller gap.




This is the final gas ring after about 100 rounds of Wolf. 100% flawless functioning. The gap in the ring is at the bottom. Sorry it's hard to see; I didn't clean it up before I took the picture.




This shows both gas rings. The one on the left is the prototype, the one on the right the final version.

I'm going to see how durable the paperclip wire is. I may end up switching to stainless safety wire; but my first impression is there is no erosion of the metal in the paper clip so I'll probably just leave it as is. Since it only takes about a minute to make the gas ring, if I had to do it everytime I shoot it, it's no big deal.

The only down side is you can't rotate the gas valve with the ring installed because it seals to the chamfer area of the gas valve and is an interference fit.

Ray

marksmak

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Yugo Gas System Fix
« Reply #1 on: October 24, 2005, 12:06:58 PM »
Thanks!!!!!!! And welcome aboard......
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galahad

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Yugo Gas System Fix
« Reply #2 on: October 24, 2005, 12:36:41 PM »
Hi, Tow4, and WELCOME ABOARD!!!!!!

That is an AWESOME fix.  I've been thinking that I should take a gas tube to the hardware store and see if I can find a SS o-ring but you've come up with the perfect solution.  I don't see any downside to that fix at all, and it doesn't change a single specification on the original rifle.   THANKS!!!!!


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dp1one

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Yugo Gas System Fix
« Reply #3 on: October 24, 2005, 12:45:54 PM »
Excellent post Tow4! I have a Yugo I'm going to try that on as well. Welcome to the boards!
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BiggAndyy

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Yugo Gas System Fix
« Reply #4 on: October 24, 2005, 12:50:11 PM »
Another item to put into the old range bag, a few paperclips.  Thanks for the tip.

jaymac

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Yugo Gas System Fix
« Reply #5 on: October 25, 2005, 09:44:38 AM »
Outstanding fix!

Hey Mods, how about making this post a sticky?
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ABC4ME

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Yugo Gas System Fix
« Reply #6 on: October 25, 2005, 07:32:16 PM »
I bought a ball bearing at my local hardware for 35 cents and it solved my malfunctioning problems.  Just make sure you apply light pressure in a vice,  check fit, and continue this until you get the right fit.  I fixed two guns this way and have shot over 500 rounds in each without any problems.

SKSDAD68

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Yugo Gas System Fix
« Reply #7 on: November 01, 2005, 07:50:01 PM »
Someone please elaborate on this ball bearing fix a bit more please. I dont quite understand. :?

Jedal Zhan

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Yugo Gas System Fix
« Reply #8 on: November 08, 2005, 11:57:12 AM »
Well, to elaborate, the ball bearing method involves smashing a portion of your rifle out of original shape. Thats something I wouldn't want to do to my rifle, even if it was a $99 beater.

Here's a handy tool that you might pick up if you see one at a flea market or for cheap. They sell new for $20 which even at that is a good deal IMO. Its a ring mandrel used for jewelry production. I got one from my grandmother who was into jewelry. I have made a total of one ring with the thing, however, I use the mandrel often for unintended purposes. Its graduated cylinder offers an infinitely accurate sizer for round objects.
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1952Sniper

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Yugo Gas System Fix
« Reply #9 on: November 08, 2005, 01:21:12 PM »
How did I miss this thread before????

The paperclip fix seems to be an excellent, yet simple fix.  I'll be interested to hear feedback from people who try it to see how long it holds up.  If you could keep a rough log of how many rounds you shoot before it blows out (if it ever blows out), that would be helpful.  The only thing I'd worry about in the meantime is whether the plating chips off of the paperclip.

Did you find the gas tube difficult to reinstall with this in place?

I assume you bent the paperclip slightly larger than the ID of the flared portion of the tube so that it would fit in there kinda like a spring and hold itself in place.  Is this the case?

One last thing... to make it easier for others to try, could you measure the length of the trimmed paperclip (before bending into a circle)?  That way others don't have to do the trial-and-error process to get the gap down.

Excellent idea!  Very ingenious!

Tow4

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Yugo Gas System Fix
« Reply #10 on: November 09, 2005, 10:57:57 AM »
I didn't have any problem installing the gas cylinder with the ring in place; but the fit may vary from rifle to rifle. If you have a problem getting the cylinder on, just leave a slightly larger gap (shorten the wire length) and put the gap on the side of the cylinder away from the barrel (as shown in my first picture) to give yourself more clearance. You can see that my first attempt had quite a large gap and functioned flawlessly.

The wire is springy so even if you wrap it around a much smaller diameter mandrel it will spring out to a larger diameter. Just cut the wire a little longer than necessary and test fit it in the gas cylinder. Cut it off a little if required. As I said before, the gap isn't critical.

I don't know if the plating will flake or burn off. The wire diameter of the paper clip is .031. You can get stainless safety wire that size if you like. In fact that's what I'm going to use on my other SKS. It functions pretty reliably but every now and then it will fail to cycle completely so I'm going to see if this fixes it.

Ray

Glane5910

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Gas tube replacement
« Reply #11 on: November 14, 2005, 10:43:03 AM »
I had problems with my 59/66 (2 of them). I made a stainless gas valve body (the gas shutoff valve body for the grenade launcher)on my lathe/mill. It works great. Before, it was also blowing primers on the HP ammo as I have seen being a problem in other posts and not ejecting rounds well. With the new valve body, function is perfect and no blown primers. It takes me about 2-2.5 hrs to do one, but could probably get faster at it but I do it by hand without CNC help. I just have a combo machine out in my shop. If anyone is interested in one of these I can make you one and ship priority mail for $25.00 US. If you don't want stainless, I could use cold rolled or try and find some moly for a little cheaper. The stainless eats up my tooling but these plugs should last basically forever. I can leave polished and you can pick your finish(not much of it shows). I may buy a powder coater or use a bake on finish if I get enough interest. You can email me at
Glane5910@aol.com
Greg

chupacabrachus

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Yugo Gas System Fix
« Reply #12 on: November 14, 2005, 11:32:12 PM »
In your first post you said you bought a replacement gas valve.  Where can I get one of these?  Thanks in advance.
Chus estaba aquí.

Glane5910

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Yugo Gas System Fix
« Reply #13 on: November 14, 2005, 11:38:38 PM »
Quote from: chupacabrachus
In your first post you said you bought a replacement gas valve.  Where can I get one of these?  Thanks in advance.

No, I made them for 2 of my 59/66. Sorry if you misunderstood. Look at my earlier post for info to buy. Thanks..You can email me
Glane5910@aol.com
Greg

chupacabrachus

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Re: Yugo Gas System Fix
« Reply #14 on: November 14, 2005, 11:55:00 PM »
Quote from: Tow4

I ordered a gas valve from Heddonpal. The valve I received was in much better condition than the worn out valve, but not as good as the valve in my good SKS.


I found it, heddonpal.com.  However it says, "Sorry, This Item Is Not Available For BackOrder".  Does anyone else sell the shut off valve?
Chus estaba aquí.