The ultimate muffler mod thread

[Four Paws]

Does anyone do muffler mods anymore? If so, post up your saw model, pictures, and description. If this thread shapes up decent, maybe it will get 'stickied'.

I'll start.

Saw: Shindaiwa 757

The muffler is built well but fairly restricted. Just look at the OE outlet. I really like the 046 Stihl dual port, so I wanted to clone it.



Step 1: clean muffler and layout. I bead blasted it and used vinyl pinstriping tape.



Step 2: cut. I used a pneumatic cut off saw with small 3" thin wheel.



Step 3: layout new design on sheetmetal. Cut and bend up in vise. Check fitment.



Step 4: weld or braze. I did both as I needed to repair some other areas. Cut port. Drill, die grinder or file as desired. Bead blast again.



Step 5: paint and install. Notice how I opened up the OE exhaust outlet as well.



Step 6: Go cut wood, burn more gas, make more noise.

 

[cgraham1]

Looks good! I try to keep mine simple...

Dolmar 7900 w/ Husky deflector...


372xp (not mine), very simple, no welding...

 

[Beer Gut]

This is the standard I use. Husky deflector. This is a 660.
This is the latest on a 020AVP. Not a duel port but way less restricted.
This is the 046 due to crankcase wing no room for Husky deflector posted above, so this is a purchased one. But it work nice.

All have stock port opened as well and any baffles cut out if present.

I have found that both holes in the muffler should add up to a combined total of 80-100% of the size of the exhaust port of the jug or I have had trouble at idle. But not in every case.

 

[Deets066]

066 triple port, no baffles or screens whatsoever

 

[Beer Gut]

View attachment 368714 066 triple port, no baffles or screens whatsoever

Is your sprocket cover custom? Or do they make one that wide?

 

[Dieselshawn]

Ms260 dual port muffler, courtesy of Mastermind.

 

[Deets066]

Yup, they come from stihl like that. They come stock on the "R" models.

 

[Flat47]

Looks good! I try to keep mine simple...

Dolmar 7900 w/ Husky deflector...
View attachment 368665

372xp (not mine), very simple, no welding...
View attachment 368666

How'd that 7900 respond to the muff mod? Been thinking about doing a mod to mine.

 

[big t double]

Took a page out of the lakeside thread for the 361. Used the ts400 screen and clamp also.

 

[cgraham1]

How'd that 7900 respond to the muff mod? Been thinking about doing a mod to mine.

It doesn't do much on a stock 7900.

 

[Flat47]

It doesn't do much on a stock 7900.

Huh, that's too bad but good to know. At least that keeps the Dolmar out of the shop (for now).

 

[cgraham1]

Huh, that's too bad but good to know. At least that keeps the Dolmar out of the shop (for now).

The good news is they are friggin' awesome without doing anything to them!

 

[Tree Sling'r]

View attachment 368699
This is the standard I use. Husky deflector. This is a 660.View attachment 368700
This is the latest on a 020AVP. Not a duel port but way less restricted.View attachment 368704
This is the 046 due to crankcase wing no room for Husky deflector posted above, so this is a purchased one. But it work

All have stock port opened as well and any baffles cut out if present.

I have found that both holes in the muffler should add up to a combined total of 80-100% of the size of the exhaust port of the jug or I have had trouble at idle. But not in every case.

On the 460, bend one end of the exhaust defector, Mark, make your hole. Install above the crankcase. I've done 100's.

 

[Big_Wood]

i'm a welded pipe fan the 066 wasn't me although i have done many similar just not as ugly or poorly done.

 

[MillerModSaws]

Gotta add the sleeper look. Ms441

 

[old-cat]

MS 361 with huge spark screen buried inside

 

[cgraham1]

Here's a pretty simple muffler mod I did on my 359... Drilled about a 5/8" hole, and I made the deflector out of some thin sheet metal and massaged it into shape with a hammer! Added a screen the same size as the deflector, and screwed it on with some SS screws... and added a thick coating of high temp paint! It's not even that loud, and the stock port on top is still functional... it's a cat muffler, so I'm not sure how much actually flows through the top port?

 

[ColdStihl]

MS-291C-BEQ



Had to pull the limiter to tune it properly. Modified the cap as such:


Here is why:


The stop pin. This also helps keep the limiter cap in place; after modifying the cap, it still does it's job. Grind the cheaper part!

The cap was replaced into the carb and now I have about 3 full turns from closed. It will work without the cap as the adjustment can be made with a metric Allen wrench, but it is a PITA with the covers on and saw idling. So, modify the cap with a Dremel cut-off disc (easiest way) and you can use the little orange screwdriver.

 

[cgraham1]

Stupid IOS 8...

 

[ColdStihl]

Added/updated my mod in Post #18.

The ultimate muffler mod thread