Need advice on MS241 muff mod

[Coolcraigster26]

Want to muff mod my MS241c. Havent seen much info on doing this. Saw is stock. I saw where Brad was putting fins on the side of the muffler. Should I do the fins to make it a dual port or just open up the factory port?

 

[huskyboy]

Want to muff mod my MS241c. Havent seen much info on doing this. Saw is stock. I saw where Brad was putting fins on the side of the muffler. Should I do the fins to make it a dual port or just open up the factory port?

I’d try gutting the factory outlet first

 

[Coolcraigster26]

I opened up the factory outlet about as much as I could but haven't tried it out yet. One thing that's wierd is it doesn't seem any louder. Looks to be some sort of baffle maybe in the top by the outlet but I don't see a way to get in there any do anything about it

 

[Coolcraigster26]

Also how does this saw respond to timing advance?

 

[Ketchup]

If it's like a 261 your muffler has a tube baffle that runs the length of the top of the muffler. It has two small holes in it that restrict flow. The gills Brad Snelling put in his muffler make another exit that doesn't mess with the baffle. It also doesn't allow you to install a spark arrestor screen. If the screen is needed, you need to attach a secondary deflector over another hole. Here's a goofy looking one that works great.


This 261 gained a lot from a 5 degree timing advance. 241 is a very similar saw, so similar results are likely.

 

[Coolcraigster26]

I don't remember seeing a tube in the muffler. I will have to look again

 

[Ketchup]

It looks very similar to a 261 muffler, so I'm assuming it has the same baffle. It might not.

The baffle is hard to see. It's in the top of the muffler and runs perpendicular from the exit port you enlarged. The screen seats inside the baffle in a track. The baffle has two holes that face the front of the muffler above the entry port. It can be opened up, but it's very difficult to do it neatly. In a 241 it may be impossible because everything is smaller. Because it's such a pain to get to, it's easier to make a new exit port somewhere else in the muffler wall.

 

[Coolcraigster26]

It looks very similar to a 261 muffler, so I'm assuming it has the same baffle. It might not.

The baffle is hard to see. It's in the top of the muffler and runs perpendicular from the exit port you enlarged. The screen seats inside the baffle in a track. The baffle has two holes that face the front of the muffler above the entry port. It can be opened up, but it's very difficult to do it neatly. In a 241 it may be impossible because everything is smaller. Because it's such a pain to get to, it's easier to make a new exit port somewhere else in the muffler wall.

I will take it back off and look inside when I get a chance. That's would make alot of sense as to why it really didn't get any louder when I opened up the port. Thanks alot for the advice. Can't wait to get home and look at it now

 

[Coolcraigster26]

Just FYI. My MS241 muffler does NOT have a baffle. It is open at the top. If I look through the port where the exhaust comes in I can see light through the outlet hole. Only thing that's in there is in the top corner where the exit port is, there is a rail made into the muffler that holds the screen. Other than that there is not a baffle in it. Nothing running across the top of the muffler. So I guess that means it's not similar to the MS261.

Interesting...

 

[Willard]

Yes there should be a ledge that holds the screen in place and the slot in it for the exhaust to flow through is the same area size as the main outlet.
Did my 261 recently and was able to grind that ledge out after enlarging the main outlet.
Looks a bit rough but the screen I mounted covers it up nicely.
To do a proper job the deflector cover needs to be removed but I needed the saw the next day.
I like the sound of a big single outlet muffler plus with the deflector cover it's in the proper location where it was designed to be.

 

[00wyk]

Damn. Did you at least buy that muffler a drink first?

I am gonna have a look at a 241 this weekend I have been asked to repair. I'll see about the baffle.
This is the work I usually do on a 261 exhaust:

The results:

 

[00wyk]

I opened up the factory outlet about as much as I could but haven't tried it out yet. One thing that's wierd is it doesn't seem any louder. Looks to be some sort of baffle maybe in the top by the outlet but I don't see a way to get in there any do anything about it

If it has a baffle on the top like the 261 does, you have to get in there with an extended bit and grind away to allow the exhaust to exit straight to atmo. Stihl does make multiple versions of mufflers as evidenced by the fact my image above has no screw hole to mount a spark screen, whereas Willard's does. It's worth it unless you don't like noise. I was always unimpressed when I saw folks MM the 241 and 261 and get like a 10% difference. When you remove the baffle on the 261, it becomes an entirely different saw.

 

[Ketchup]

A timing advance and carb delimiting were very helpful to gain more on my 261. I felt it gained more from the advance than the MM. I would assume it would help on a 241 also. You can always put the timing back if it doesn't help.