fail-safe compression valves

[chainsaw lover]

Love using, tuning and working on chainsaws. Say, anyone out there know where to buy fail-safe decompression valves ?

As a collector of chainsaws, over the years have heard a few horor stories about deComp valve stems breaking or comming loose and falling down into the piston chamber.

And, recently viewed a YouTube Vid where one dude was modifying his Stihl MS-660, Farmer'H 660 and Neo-Tec 660 using "fail-safe" decompression valves he bought off eBay.

But couldn't find them there or elsewhere (so far) -searched hi-&-low/to-&-fro to find them with NO RESULTS.

QUESTION: Anyone out there know where someone can buy these little jewels ?

By looking closely at the video it appears that there is a "pin" through the button on top which prevents the button from flying off when it pops-up.

PS: Bought a couple Neo-Tec 660's heads (MS-660 clones) from Amazon but just got them in yesterday and haven't went thru them yet for Mod's.

Thankx

 

[SimonHS]

Genuine OEM Stihl or Husqvarna decompression valves are safe to use. Most clone 660 builders throw the Chinese valves away, for peace of mind.

 

[bwalker]

The fool proof way is to replace the valve with a plug. I hate decomp valves. For starters they all leak. This doesn't really cause any issues that I have seen, but it drives me nuts.
They are a necessary evil on ported saws and saws above 80cc.

 

[chainsaw lover]

Genuine OEM Stihl or Husqvarna decompression valves are safe to use. Most clone 660 builders throw the Chinese valves away, for peace of mind.

Yes, chuck those Chinese deComp's and replace with genuine OEM...same for spark-plugs...I go for the NGK's.

I have several Husky's and Stihls and throughout decades of use have never had any deComp problems...however, some stories include those brands since parts for them come different countries now -country of orgin New World Order globalized economy stuff.

I haven't used the deComp valve for what seems like decades. Use to be Husqvarna made in Sweeden, and Stihl in Germany. But you gotta buy them in-country (EU) to get that craftsmanship. As you might already know, buying a Stihl in USA, they are assembled in the Virginia Beach, VA plant; and Husqvarna with same story.

I don't drop-start, always put the big saws on the ground and watch the young vendor guys drop-start while I have the camera ready for the one without chaps crank that 660 or 880 to set the example for a Kodak moment to go viral on YouTube -just kid'n.

I quit using the deComp valve many-a-moon ago and pull the cord lightly to find the tdc then crank that big bore beast...
With 50cc or less just Go For Broke (442d Inf) and don't wory about finding TDC, just pull the rip-cord.

Thankx for taking the time for reply.

 

[chainsaw lover]

The fool proof way is to replace the valve with a plug. I hate decomp valves. For starters they all leak. This doesn't really cause any issues that I have seen, but it drives me nuts.
They are a necessary evil on ported saws and saws above 80cc.

Oh yeah, that was another question... super idea...I was wondering if that would work on most chainsaws engines.

Believe that is the answer for several of my saws.

PS: Got to check out Kazakhstan.

 

[Ted Jenkins]

For most part I do not use or like decomp valves period. then there is the time and place you need one to be operational. I found some one from Germany who said they had extra OEM but not positive. I compared to Stihl OEM and yes every thing points to OEM so anyways bought several. What I do for reliability is cut the grooves much wider so I can put thicker washers on both grooves. I put a lite spring under the bottom groove then the washer which I will braze shut then repeat for the top groove. I have checked several times to discover they are not leaking probably due to extra tension. Thanks

 

[cuttinstihl]

On the question of decomps and plugs for decomps, does anyone here know where to find a plug for the CS590 decomp? It hasn’t leaked at all yet but I’d feel more comfortable plugging it

 

[ballisticdoughnut]

On the question of decomps and plugs for decomps, does anyone here know where to find a plug for the CS590 decomp? It hasn’t leaked at all yet but I’d feel more comfortable plugging it

I had to make a plug for my CS600P because the thread is 10X1.25 instead of the more common 10X1.0 Stihl and Husky uses. I used a Honda GX160 oil drain plug but you have to cut it down on a lathe, the threaded portion is too long and will protrude into the combustion chamber. Don’t forget to use a crush washer on the plug.

 

[cookies]

Every one hates a decomp valve until you get your feelings hurt in all 5 digits, wrist and elbow when a little extra oil or fuel accumulates in the rings. I find soaking a leaky decomp in diesel or carb cleaner a day or three then opening it and brushing it with a stainless bristle brush often gets it sealing p and functioning properly again. Oem only if replacing it as I would not trust a knockoff to retain integrity in the metal valve face after many heat cycles.

 

[Cedar Row]

The decomp on my 361 is stuck in the down position because the saw won't fire. Any chance the decomposition could be the problem? I didn't want to force it up without further information.

 

[cookies]

My saws will pop it back up every pull without it kicking over, i'd remove and soak in diesel the attempt to clean the carbon out of it