Muffler Mod question (ms290)

[SpikeDmax]

Where do I drill the holes? Right in the center of the depression? Two 3/8" holes, correct? Then trim back the deflector? Adjust carb and go.

 

[bitzer]

That will do it. I've made just one big hole on the ones I've done and then widended the hole on the deflector. Get ready for a new feeling saw! If you do a search on 029 or 290 muffler mod you will get some pics of what others have done.

 

[timberwolf]

You can make the existing holes bigger or just add a new hole, the center of that hollow is a great place. Also you will likely need open the outlet on the defflector a little too.

 

[SpikeDmax]

If I go with 1 hole in the center what size should it be? Also, how does one open up the deflector? Dremel and cut off wheel?

 

[bitzer]

I've done two of these mufflers. The first one I used a 1/2" bit down the center of the depression. Eventually I went back into it with a dremel and a carbide bit and opened it up more. The second one I dilled a 3/8" hole in the bottom right corner of the depression and that saw is a lot quieter, but it also dosen't have the flow of the bigger hole on the first one. Yes use a dremel and carbide bit or rasp to open up the defelector. I also put a second hole in the deflector opposed to the original opening.

 

[Evanrude]

Here is how I do it. This was my first muffler mod I ever did so its not the best looking. But I still do it the same way with the 6 holes and it makes those saws a totally different animal. Just make sure to trim your limiter tabs and readjust your carb. The second pic shows how I open up the deflector.

 

[SpikeDmax]

By doing this Mod were are basically 'straight piping' the exhaust as the port is directly behind the modified opening? That has got to make it loud. Would leaving the defection port alone keep it quieter at the expense of hp?

 

[timberwolf]

The more you open the exhaust the louder it gets. Most of the gains can be had in the first doubling or so of the existing opeing which makes only a slight jump in the sound after that you get more and more sound to get smaller and smaller gains.

I just added a very mild 3/8 x 1/2 opeing and slight grind on the defflector for an 029 this weekend. It made a nice difference in how the saw ran without making it much louder. Also was able to adjust the carb to get enough fuel without removing the limiter caps.

 

[HittinSteel]

By doing this Mod were are basically 'straight piping' the exhaust as the port is directly behind the modified opening? That has got to make it loud. Would leaving the defection port alone keep it quieter at the expense of hp?

Don't worry about the noise. I never messed with the deflector when I did mine, just dremeled a single hole and made a "straight thru" exhaust. Get good muffs or ear plugs and be ready to grin.

 

[Axlerod74]

The more you open the exhaust the louder it gets. Most of the gains can be had in the first doubling or so of the existing opeing which makes only a slight jump in the sound after that you get more and more sound to get smaller and smaller gains.

I just added a very mild 3/8 x 1/2 opeing and slight grind on the defflector for an 029 this weekend. It made a nice difference in how the saw ran without making it much louder. Also was able to adjust the carb to get enough fuel without removing the limiter caps.

Any chance you have a picture of this mod? I would like to mildly mod my Dad's saw without having to remove the limiters.

 

[HorseFaller]

The pro shop that did my ms390 pretty much made it straight thru. When you removed the cover and screen you could see the piston. It was louder then my 44 triple ported. But was able to pull a 28" b/c moderately.