The ultimate muffler mod thread

[Four Paws]

I enjoy working on vintage saws. Generally, it is impossible or extremely costly to find replacement parts, so you end up working with what you have. These mufflers came off some old magnesium I am working on, and were due for a facelift and spark arrestors.

First thing I do is degrease them - you can use solvents, but I prefer to toss them on a bed of coals in the wood stove for 10 minutes.



Once they have cooled, into the blasting cabinet.



After the rust is removed, I blow them off, and get them nice and hot on the woodstove.



After about 15 minutes, time for paint. I hook a wire through a hole so I can hang the muffler while I paint. Painting hot cures the paint nearly instantly, and really seems to improve adhesion and durability of the coating. I use Krylon BBQ and Stove paint.



I cut the spark screen from a cheap dollar store kitchen strainer.



All finished up. Not perfect - there are some dents and some pitting. Just right for a vintage saw that is getting a new lease on life and will be put back in the wood where it belongs!

 

[CapitaineHaddoc]

They look really nice, great work

 

[Sty57]

I do the same thing on all of my saws.....I hate rusty mufflers. I don't know why it bothers me so much but it does.

 

[slovcan]

Hi guys,

I just put the modded muffler on my 346XP. Unfortunately I haven't had time to run it yet, but I have both L & H set at 1.5 turns as a starting point.

I bought a perfect OEM muffler for my 346XP from aducomb. He had already opened up the top outlet to the full size of the deflector top cover. It's just an empty can really, don't know why they call it a muffler! It should be a dramatic change from the cat muffler that came on it.

First I used a Sharpie to mark under the new 288 deflector and the screw holes with it positioned where I thought it should go. I kept it narrow enough so all the exhaust would be deflected forward. Next I bent the top end of the deflector to fit the top curve of the muffler.Then I made the dimples for the pilot holes with centre punch - hand pressure, no need for the hammer. I drilled a 7/16" hole at each end of the Sharpie oval and the screw holes. There was likely 1/8"-3/16" between the holes. I cut that out with tin snips.



Then I used a flat and a round file to clean up the hole. Then shake out and blow out the filings from inside - easy with an empty can. I figure the finished size of the hole is just a tad over 7/16" wide by 1-1/16" or 1-1/8" long.



I used sheet metal screws with lock washers to put the deflector and screen on. I hope they hold. I don't like the idea of having nuts or bolts inside the muffler in case they should come loose. Here's the finished product.





Can't wait to run/tune it!

Cheers,
Glenn

 

[Ronaldo]

I like pipes. They usually give the saw a deep, throaty tone. Harder to screen, though.

 

[nyctreeman]

Why mod a muffler and then stick a spark arrestor in it?
Spark arrestors belong on woodstove chimneys, not chainsaws.

 

[Ronaldo]

Why mod a muffler and then stick a spark arrestor in it?
Spark arrestors belong on woodstove chimneys, not chainsaws.

In some locales they are required, like forest service ground.

 

[blk05crew]

My first and only muffler mod so far. Done on my Poulan 3400. Simple and easy but it works.

Drilled out the holes inside the muffler to a larger diameter.



Cut a slit in the side of the muffler body and heated it up and pried it open.

 

[pond hopper]

Recent mod on my 660. Opened up muffler and revamped side deflector

 

[PA Dan]

Modded my 262xp this weekend! Removed the deflector and cut the baffle out. Added a piece of 14 mesh screen when installing the deflector. After finishing I decided im cutting those fingers off the deflector and going to do a custom rounded flare on it. Here's the pics and the final one will follow when finished.

 

[Magnum783]

I use header paint to paint my mufflers not as nice of a finish but holds up great

 

[PA Dan]

I use header paint to paint my mufflers not as nice of a finish but holds up great

I have used it also but now Glock37 is doing hi temp powder coat in satin black. I will have this one and my 064 done and see how it holds up!

 

[Magnum783]

Keep us posted I am curious how this will hold up.

 

[Red Amor]

this is the muffler off my MS 310 , pretty much doubled the size of every hole the thing goes very well for its size
and creates a lot of interest when others are about , most think it sounds and performs as a much bigger saw
I really like to use it , its light and can lean on the cut if you feel the need to can run 20" 3/8 nicely
some of the fellers on here remove the baffle cage altogether , I chose to leave it in to hold the thing together as I had nothing at hand to spacer the mounting bolts

 

[Rx7man]

I haven't done very much to my chain saw mufflers, but I found empty 1 lb propane bottles (stubbies or tall ones) work really nicely as a starting point for mufflers on most small engines.. Unscrew the schrader valves with a tire valve tool, fill right full with water, then cut it up. For packing I sometimes used coarse drill swerf held down by a perforated plate. I found various sources of pipe that work really nicely.. Jack handles, tent poles from large tents, handlebars, etc.

For motorcycle mufflers I found old driveshafts work nicely when cut up

 

[PA Dan]

Modded my 262xp this weekend! Removed the deflector and cut the baffle out. Added a piece of 14 mesh screen when installing the deflector. After finishing I decided im cutting those fingers off the deflector and going to do a custom rounded flare on it. Here's the pics and the final one will follow when finished.

Here's my progress with the deflector! I removed the finger things and started forming the curves. Starting to look good! Ill work it a little more and then work on making it all even and smooth. Then off to be powder coated!

 

[Rx7man]

Here's mine... The guts are all hollow, and the baffle behind the deflector got chopped in half. The baffle right after the exhaust port got eliminated completely and it got port-matched as well.
I haven't really run it much, just in the shop a little.. Hope to put it in some wood tomorrow and take a vid of it. It's sounding like a very happy 65cc saw now anyhow

 

[slovcan]

Hi guys,

I just put the modded muffler on my 346XP. Unfortunately I haven't had time to run it yet, but I have both L & H set at 1.5 turns as a starting point.

I bought a perfect OEM muffler for my 346XP from aducomb. He had already opened up the top outlet to the full size of the deflector top cover. It's just an empty can really, don't know why they call it a muffler! It should be a dramatic change from the cat muffler that came on it.

First I used a Sharpie to mark under the new 288 deflector and the screw holes with it positioned where I thought it should go. I kept it narrow enough so all the exhaust would be deflected forward. Next I bent the top end of the deflector to fit the top curve of the muffler.Then I made the dimples for the pilot holes with centre punch - hand pressure, no need for the hammer. I drilled a 7/16" hole at each end of the Sharpie oval and the screw holes. There was likely 1/8"-3/16" between the holes. I cut that out with tin snips.

View attachment 399292

Then I used a flat and a round file to clean up the hole. Then shake out and blow out the filings from inside - easy with an empty can. I figure the finished size of the hole is just a tad over 7/16" wide by 1-1/16" or 1-1/8" long.

View attachment 399293

I used sheet metal screws with lock washers to put the deflector and screen on. I hope they hold. I don't like the idea of having nuts or bolts inside the muffler in case they should come loose. Here's the finished product.

View attachment 399294

View attachment 399296

Can't wait to run/tune it!

Cheers,
Glenn

OK, ran it and tuned it. It's not as loud as I thought it might be going from a stock cat muffler to an empty can. Starts and runs great. I have the L set at 1 turn and the H ended up at 2 turns. At 2.5 turns it was 4 stroking and a bit flat and slow at max revs and smoking quite a bit (I mixed at 40:1). At 2.25 turns still 4 stroking, a bit slow but no smoke to speak of. Right at 2 turns it 4 strokes just a bit, sounds like pretty high revs and no smoke. Cutting tiny cookies it is clean in the tiny cut - no 4 stroking and still high revving. I should find a bigger stick to cut!

I don't know what kind of carb I have, but my settings do seem way different than some others have mentioned here in reference to their 346's with a muffler mod. For sure mine wouldn't run at all with 2.5 L and 4 H!

I am happy! This thing seems like a little monster to me (but then again, I haven't experienced a 60-70 cc saw yet ).

On another note, I am having second thoughts about my choice of 3/8" chain over .325". I see now what some guys say about the 3/8" being rougher. I see the slightly rough end when cutting the tiny cookies and expect the .325" might be noticeably smoother. On the other hand, does that really matter for firewood? No. So, I guess no second thoughts after all...

Cheers,
Glenn

 

[Mastermind]

I'm here now.

 

[Four Paws]

I'm here now.

Way to get with the program