MS 260 Pro Muffler Mod?

[Wind Walker]

I did some searching with no luck, just looking for some info on what's involved with doing this. I'm sure there is a thread with detailed instructions, I guess I'm just searching the wrong things. Anyone point me in the right direction so I can gather some info on this?

Oh my saw does have the high and low adjustment.

Does it hurt the life of the saw? Any reason not to do this?

I'm pretty happy with the saw the way it is, but I guess it's just my nature to tinker. I figure if it doesn't work out I'll just get a new muffler. If I can add a bit of power without any money spent or reducing the life of the saw it sounds like a win/win situation.

Thanks

 

[oscar4883]

It is not going to hurt the saw one bit. With a T-27 take the muffler cover off. You should see one hole on the inside of the cover. It will be on a slightly raised portion IIRC. Drill a hole of the same size above and below the existing hole. You can even slot them together if you would like. Remove any burrs and clean REAL well. Done. The important thing is to be able to tune the saw properly when done. I can grab a pic later if my instructions are poor. LOL

 

[Bubbles Up]

With the forum change there was an awesome thread on here,where a person on here who did a 260 pro muff mod,where he actually did put down hard facts like noise in db,temp and RPMs as he did a progressive muffler mod. I wish I could find it again too as I have a 260 that is screaming at me for a muff mod then send it away for a full port job.

 

[oscar4883]

Can you Muffler Mod To Much???

Post 9 has a link to the thread in question. I couldn't get the link to work for me but maybe you guys will have better luck with it.

 

[Wind Walker]

Thanks

Yeah that link didn't work for me either.

So I guess I'll end up with three holes instead of one. That sounds pretty simple for sure.

What's involved with tuning afterwards? It is as simple as turning the screws till she sounds good, or more complicated? Is there a general way to start with tuning after the MM? Such as which direction to turn either screw and how far?


Mike

 

[oscar4883]

Member blsnelling has a youtube page and if you search tuning several vids will come up. Counterclockwise richens the mixture and clockwise leans it. I would back the high side screw out a 1/2 to start. The lowside may be close enough. Put the saw in some appropriate sized wood and make a cut. If you open it 1/2 it should be pretty rich and will sound rough in the cut. The term is "four stroking". Gradually lean it out until it cleans up in the cut for the most part. Where in Penns Woods are you?

 

[Frank Boyer]

Three 3/8" holes make a huge difference on a 026/260. Lakeside did a great how to on the subject. Open the origional hole up. Then drill a hole above and below the first hole. Last is reset the carb.

 

[sbhooper]

The 260 is just an OK saw without a muffler mod. It is a bit weak. I did a mod on mine and it makes it a totally different saw. I absoulutely love mine. I prefer to use it over my others within its capabilities and it is definitely the easiest-starting saw that I own. With the 16-inch/.325 it does a great job. Do the mod!!

 

[Wind Walker]

After a good weekend of cutting I cleaned the saw up tonight and sharpened the chain. Then I pulled the muffler off to check it out. Everything looks pretty straight forward. I was very surprised at how small the one hole is.

I was also checking the high end screw, it looks as if there is a red plastic piece around the screw, is this some sort of limiter? Does that need to be removed?

Pine Grove, Pa.

Mike

 

[Frank Boyer]

The red cap needs to be removed. The current ones have a tang that sticks out and that limits the H adjustor travel. The tang lines up with the slot to remove it when the red cap is turned to the right. Stihl makes a tool to remove the adjustor and a friendly dealer may sell you the tool. Others have used a sheet rock screw to remove the red cap. Once you get a bite with the tool/screw turn the red cap to the right before you try to pull it straight out.

 

[CWME]

Three 3/8" holes make a huge difference on a 026/260. Lakeside did a great how to on the subject. Open the origional hole up. Then drill a hole above and below the first hole. Last is reset the carb.

I just did this tonight on my 260 pro Christmas present. Holly cow what a difference. Fresh ground chain, 8 pin rim, MM, = one hell of a limbing saw...

Burried the bar in a 16" beech log tonight and it muscled through it with little effort. Before it would bog down. Completely different saw. I was disapointed when I got it but not any more. Definately worth the 5 mins it took.

 

[Shmudda]

It is not going to hurt the saw one bit. With a T-27 take the muffler cover off. You should see one hole on the inside of the cover. It will be on a slightly raised portion IIRC. Drill a hole of the same size above and below the existing hole. You can even slot them together if you would like. Remove any burrs and clean REAL well. Done. The important thing is to be able to tune the saw properly when done. I can grab a pic later if my instructions are poor. LOL

I went and did this mod to my 026 Pro this evening. I can tell from the sound it will pull and cut better, just need to get to the weekend to get it into some wood to see if the carb adjustments are right. Took all of 15 minutes.

Thanks Oscar.......

Craig

 

[Frank Boyer]

Ritchen up the high side before you go cutting.

 

[Wind Walker]

Need alittle help with getting the red limiter out.

I turned the adjustment screw all the way to the right, then I inserted a drywall screw and turned that in a bit. The red part moves in and out but doesn't want to come out alltogether. It hardly looks like the red plastic part will fit out through the small hole. I'm leary of damaging something, mainly the high adjustment screw.

Would it be better to pull the carb?

Thanks for any more details on removing the red plastic POS.

 

[Mntn Man]

You have to take the carb out, at least I did.

 

[Shmudda]

Ritchen up the high side before you go cutting.

I will Frank. There is no time for me during the week due to work and kids, thats why I need to wait until the weekend. I need to get my cousin's electronic tach to help adjust the RPM's at WOT. I'm seeing from another thread by Windthrown on Tree World the factory RPM's of this saw and a few other Stihl's is 14K +/- 500, so I will be shooting for that.

I was playing with H/L adjustments on the saw last night and I can plainly hear the 4-stroking some are talking about, I just need to get it into a log to make the final adjustments.

This is my first experience doing this, so I'm gathering info and learning. I love this saw and will take my time to do the adjustments right.

Craig

 

[PogoInTheWoods]

I need to get my cousin's electronic tach to help adjust the RPM's at WOT.Craig

You don't tune a modded saw with a tach. The specs have been altered by the mod. Setting up a modded saw back to factory specs sorta defeats the purpose anyway, doesn't it?

Poge

 

[Shmudda]

Poge,

Just relaying what I am reading, as this is my first attemp at a muffler mod. You really are not setting anything up except the WOT RPM's. I will tune it so that I have a slight worble (running rich) at WOT, and adjust it until it goes away under full load with the bar in a log. I want the tach to ensure I'm not over reving the engine, I dont want it to scatter and run to lean on me. Keeping the RPM's on the low end with the H valve adjustment means that it's running a little rich, and from what I am reading from many different people thats right where you want to be.

Craig

 

[PogoInTheWoods]

Poge,

Just relaying what I am reading, as this is my first attemp at a muffler mod. You really are not setting anything up except the WOT RPM's. I will tune it so that I have a slight worble (running rich) at WOT, and adjust it until it goes away under full load with the bar in a log. I want the tach to ensure I'm not over reving the engine, I dont want it to scatter and run to lean on me. Keeping the RPM's on the low end with the H valve adjustment means that it's running a little rich, and from what I am reading from many different people thats right where you want to be.

Craig

Craig,

Compared to what?

If you're going to combine the tach approach with the ear approach, tune the saw by ear before you mod and see how close you are to spec by checking with the tach to see how far off you actually were and in which direction. Do this a couple of times to get a feel for the process. Then tune to spec with the tach.

Now do the mod. Tune by ear as before. Check it with the tach again.

Let us know your findings. I'll bet you gain just a few RPM's with the mod and re-tuned carb that you won't want to give back even though the tach says you're running a little "fast" compared to spec at WOT now!

That's kind of why you do the mod -- not just to make the saw louder.

More air flow plus more fuel usually equals more saw -- an out of spec one.

(Not bustin' your chops. Just tryin' to clarify.)

Good luck with it and let us know how it turns out.

Poge

 

[tipomac]

Muffler Mod, how BIG is too BIG

Can you Muffler Mod To Much???

Post 9 has a link to the thread in question. I couldn't get the link to work for me but maybe you guys will have better luck with it.

It was a post by timberwolf.
I managed to get the link to work.
Here it is.
TIP

Muffler Mod, how big is too BIG