To plug or not to plug…

[Wonka13]

So, I’ve seen this go either way, but am interested in your guy’s thought process.
To plug the cylinder decomp or not to plug, that is the question at hand. I understand the theory & purpose of the decomp, but what benefit vs. problems arise by keeping or plugging the decomp in the cylinder? One less thing to leak, yes, but more difficult to start especially in a high compression tweaked saw? Also a yes, I’m guessing, but which side of the fence are you guys on, and why?

 

[Dennisthemenace]

Under 90 cc I remove decomps as they are just something else to leak and most do, a little bit. Over that size, 660, 395 etc I reckon the starter gear gets hit too hard without em. I tried my 084 without and the answer was... NAH, won't do that again

 

[jasent]

I’m in both camps too. Smaller saws I plug. Larger saws will depend on the work done. My 2094 needs it! 461 will pop the decomp with out firing so I plugged it. 660 has one but only gets used on cold start.

 

[BayouCountryPowerSaws]

I ended up plugging mine on the 2185, but I always start my saws using the 3-point start and it makes starting super easy because of the momentum and pull angle. I cant start my 880 on the ground stationary, cant pull it over fast enough to keep it from jerking the handle from you and then you end up flooding it. I can definitely see both sides, but I remove them on everything below 100cc so far, that may change one day though lol

 

[Robin Wood]

One cool trick if you have the cylinder down is to cut compression relief groove on the exhaust port ceiling like they used to do on the old saws pioneer and others.

Especially if its getting machine work/pop up piston or any sort of compression bump

Latest saw I've seen having that design is echo cs2511t, 110 ex port timing and 100 relief groove timing i think

 

[BayouCountryPowerSaws]

Just like Mr. Robin Said above, you can see that style on McCullochs with their Q port and a lot of Partners had them as well.

It bleeds some compression when pulling it over but doesn't affect compression while running.

Partner P100 Super Cylinder:

 

[Wonka13]

I ended up plugging mine on the 2185, but I always start my saws using the 3-point start and it makes starting super easy because of the momentum and pull angle. I cant start my 880 on the ground stationary, cant pull it over fast enough to keep it from jerking the handle from you and then you end up flooding it. I can definitely see both sides, but I remove them on everything below 100cc so far, that may change one day though lol

I watched your video on the start/warm-up…good stuff!!

 

[Wonka13]

One cool trick if you have the cylinder down is to cut compression relief groove on the exhaust port ceiling like they used to do on the old saws pioneer and others.

Especially if its getting machine work/pop up piston or any sort of compression bump

Latest saw I've seen having that design is echo cs2511t, 110 ex port timing and 100 relief groove timing i think

I’m having Labfab do the cylinder/piston work, so might be a good option!

 

[Robin Wood]

I’m having Labfab do the cylinder/piston work, so might be a good option!

I say go for it!

 

[Wonka13]

I think I’ll just go the decomp route for now on the 385 to make things a bit easier machining-wise…is there an alternate decomp from another Husky model that works better than the stock part in a 385? Seem to recall some discussion about it on another forum, but can’t for the life of me find it again…you know how those forums get all jumbled with info

 

[BayouCountryPowerSaws]

I think I’ll just go the decomp route for now on the 385 to make things a bit easier machining-wise…is there an alternate decomp from another Husky model that works better than the stock part in a 385? Seem to recall some discussion about it on another forum, but can’t for the life of me find it again…you know how those forums get all jumbled with info

Unfortunately I have seen both fail and they all will leak to an extent.

 

[Chris Paul]

Agree with most here, I plug decomps on anything under 90cc. Have a decent pulling arm at 51 and the saws don't seem to mind. Had a run of crummy decomps on a 362cm, went through 4 in a very short time. 2 leaked right off the shelf 2 failed during cutting. Warranty for three of em but the hassle wasn't worth it.

 

[Fabz]

get rid of the compression release and install a plug

 

[tacotodd]

I think I’ll just go the decomp route for now on the 385 to make things a bit easier machining-wise…is there an alternate decomp from another Husky model that works better than the stock part in a 385? Seem to recall some discussion about it on another forum, but can’t for the life of me find it again…you know how those forums get all jumbled with info

In “theory” the smaller displacement an engine is the less a decomp will bleed off. So if you go by that same idea I’d pick one up for a VERY small saw. IDK what the smallest cc saw with a decomp that you’ll even find is Whatever & however you end up, guluck (slowly pronounce)

 

[Real1]

I started out with no decomps on large cc saws. I don't see it as an issue, though it's a nice convenience. On my J'reds 90, the way I carry the saw running, my cotton gloved hand(knuckles) hit the decomp while walking through the woods. I plugged it.

I would be wary of saws with plastic recoils and high compression #'s. The bean counters decided that since you have a decomp, they can save money on a flimsy recoil assembly. Plugging the decomp on those saws may take out the recoil assembly prematurely.

Kevin

 

[tacotodd]

I started out with no decomps on large cc saws. I don't see it as an issue, though it's a nice convenience. On my J'reds 90, the way I carry the saw running, my cotton gloved hand(knuckles) hit the decomp while walking through the woods. I plugged it.

I would be wary of saws with plastic recoils and high compression #'s. The bean counters decided that since you have a decomp, they can save money on a flimsy recoil assembly. Plugging the decomp on those saws may take out the recoil assembly prematurely.

Kevin

Kevin?

 

[tacotodd]

As in shepherd?

 

[Real1]

Yessir! Thanks for inviting me.

Kevin

 

[Bob Hedgecutter]

If the saw came factory fitted with one, I leave them in until they give trouble (which seldom seems to happen- that cannot be fixed by cleaning out some carbon). Whether I choose to use the feature or not, is another story- some saws require it cold starting, some don't- glad my 2094 has one, not disappointed the 2100 does not.
Last one I removed or plugged was on an aftermarket (Meteor) cylinder on an old 036, but I never cared for that saw and sold it soon after.

What you don't want to do is replace a broken or missing factory decomp valve with a cheap imitation of the factory ones- odds are very good they will give leakage problems- or drop the tear drop that seats the valve into the cylinder at WOT.

 

[Real1]

Yes, it's certainly subjective. Having not started out with decomps, they don't excite me.

Like you, except for the J'reds 90 I mentioned(and why), I leave them unless they are causing trouble. Do I use them...nah.

Kevin