# Muffler Mod - MS291 style



## VinceGU05 (Dec 20, 2013)

I have done a few muffler mods now; the majority are done with dremel and carbide burr. 
But this is my first attempt at louvred style. And I think it came up pretty good. Once again dremel, slitting wheel and a few different pair of pliers.


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## gold_driller (Dec 20, 2013)

Looks good


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## 1Alpha1 (Dec 20, 2013)

Nice work, and you obviously didn't have to remove the front cover of the muffler.

It's gotta be a PITA to take that cover off.


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## VinceGU05 (Dec 20, 2013)

dano said:


> Nice work, and you obviously didn't have to remove the front cover of the muffler.
> 
> It's gotta be a PITA to take that cover off.



dont think you can. its all crimped together. easy enough to do as is.


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## 1Alpha1 (Dec 20, 2013)

VinceGU05 said:


> dont think you can. its all crimped together. easy enough to do as is.




Some members say to use a torch, heat it up good, and then use pliers to fold back the crimping.


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## jdhacker (Dec 20, 2013)

Looks great I have a ms291 how much did it help the saw after mod. As I am wanting to do mine.


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## 1Alpha1 (Dec 20, 2013)

Couldn't help but notice the price sticker on the shelf the saw is sitting on.

OUCH!!


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## VinceGU05 (Dec 20, 2013)

jdhacker said:


> Looks great I have a ms291 how much did it help the saw after mod. As I am wanting to do mine.



only done it fresh this morning. painting it matt black atm. see after xmas how it goes.


dano said:


> Couldn't help but notice the price sticker on the shelf the saw is sitting on.
> 
> OUCH!!



yeah we pay thru the nose here for the stihl stuff


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## 1Alpha1 (Dec 20, 2013)

VinceGU05 said:


> only done it fresh this morning. painting it matt black atm. see after xmas how it goes.
> 
> 
> yeah we pay thru the nose here for the stihl stuff




I'm sure that you may have considered this idea already, but how's about having someone send you a saw from the US?

Shipping couldn't be too much, but how is the import duty or tax set up in Australia? A hassle or just too much of a PITA?


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## z71mike (Dec 20, 2013)

Nice work brother. Very clean.


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## HD2010 (Dec 20, 2013)

Looks great. I did a louver on my 391 and did not turn out nearly as good as yours. Nice job.


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## John R (Dec 20, 2013)

Looks factory, nice job.


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## cre10 (Dec 20, 2013)

Looks great!


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## VinceGU05 (Dec 21, 2013)

dano said:


> I'm sure that you may have considered this idea already, but how's about having someone send you a saw from the US?
> 
> Shipping couldn't be too much, but how is the import duty or tax set up in Australia? A hassle or just too much of a PITA?



Yeah have considered it. In 2 minds to do it. The big plus would be to have a saw ported as well then send. stihlman on AS does all his saws like that.


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## jdhacker (Dec 21, 2013)

Your killing me man go run that saw!!!


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## redfin (Dec 21, 2013)

Prying the lip up is tedious but doable. I have done a few that had cats in them that I wanted out.

Very nice work on the louvers.


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## jdhacker (Dec 24, 2013)

Any update on this


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## Aahhyes68 (Dec 24, 2013)

Looks great. I want to do that to my, new to me MS 261... Will a simple mod like that require a carb tune ??


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## VinceGU05 (Dec 25, 2013)

jdhacker said:


> Your killing me man go run that saw!!!


 This is for a mate that's got bush till the weekend. Sorry.


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## VinceGU05 (Dec 25, 2013)

Aahhyes68 said:


> Looks great. I want to do that to my, new to me MS 261... Will a simple mod like that require a carb tune ??



Yeah I reckon it will. Will need to fatten up the top end. Screwdriver into the H


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## jdhacker (Dec 31, 2013)

Any updates


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## Stihl working hard (Dec 31, 2013)

If someone told me that was a factory produced muffler I would believe them outstanding workmanship well done


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## VinceGU05 (Jan 1, 2014)

Thanks SWH. 
Planning on running it tomorrow. Will try to do some b4 and after cut times.


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## VinceGU05 (Jan 2, 2014)

jdhacker said:


> Any updates



finally done.. roughly a 15% cut speed increase i think we got from it.
stock, sem chisel chain

muffler mod according to my mate had a heap more torque.

my stock 441cm for comparison with full chisel chain


my mate Justin was very happy with the MM and its performance upgrade.


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## jdhacker (Jan 2, 2014)

Hey thanks for the update, I'm not picking but looks like his chain needs some att. Anyway thanks for showing the end results.


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## rmh3481 (Jan 2, 2014)

Real nice and not too loud either.


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## VinceGU05 (Jan 2, 2014)

It wasn't the freshest chain but it wasn't that bad either. We checked it b4 starting. our wood is pretty damn hard. ! 
I was surprised too! Not much louder at all. I guess the louvers keep the noise down rather than just having a big hole.


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## jdhacker (Jan 2, 2014)

I timed it, best I could tell it was 3 seconds slower then the 441. Thats dam good going against a 70cc saw, looks like the mod woke it up. You did a great job, did you have to fatten the carb much. I will be doing mine this weekend.


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## 7sleeper (Jan 2, 2014)

Don't show the vid to ST. He will never believe that a semi pro could ever be so fast... 



7


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## Tippmann98 (Jan 2, 2014)

It's obvious that it was worth doing. Could you share what tuning you did to the saw after the muffler mod?


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## VinceGU05 (Jan 2, 2014)

jdhacker said:


> I timed it, best I could tell it was 3 seconds slower then the 441. Thats dam good going against a 70cc saw, looks like the mod woke it up. You did a great job, did you have to fatten the carb much. I will be doing mine this weekend.



Think you got the saws mixed up. 
First vid stock 291 avg 26 sec

2nd vid is with MM. Avg 23 sec

3rd vid is 441cm avg 14 sec. 

Surprisely top end was pretty close. But the bottom end needed fattening up a fair bit.


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## z71mike (Jan 2, 2014)

Tippmann98 said:


> It's obvious that it was worth doing. Could you share what tuning you did to the saw after the muffler mod?


Don't see it as a tuning 'mod'. It's a simple carb adjustment, which you should be doing often anyway. Learn how to tune a carb on here or youtube and it'll be one of the best 'performance mods' you can do for your saw. Tune often. No 2 running conditions are ever the same.


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## barneyrb (Jan 2, 2014)

Just wondering if that muffler has any internal baffling or an open can


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## VinceGU05 (Jan 3, 2014)

barneyrb said:


> Just wondering if that muffler has any internal baffling or an open can


Looked like an open can to me.


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## jdhacker (Jan 3, 2014)

Looks kinda like it has a 3/8 or so tube going around the inside of the muffler. It's hard to see, I took mine off and shined a light in the exit port, and you can not see any light on the inside of the muffler.


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## VinceGU05 (Jan 3, 2014)

Those tubes are where the screws go to hold it onto the motor. Other than that I think it's empty in there. No baffle like a 2 piece muffler on a bigger saw.


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## jdhacker (Jan 3, 2014)

No what I am saying, if you hold a pen light to the exhaust port, no light inside the muffler. I''m not talking about the tube where the bolts go. There is some type of tube on the inside I think and its very hard to see.


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## Jarh73 (Jan 7, 2014)

Thought I better reply to the thread devoted to my new muffler.

Big thanks to Vince for the time and effort of modifying the muffler!

What I wanted to add was my own perspective. 

Firstly the Eucalypt we tested on had been dead for over 1 year and I believe it is Manna Gum, a hardwood. 

What is hard to get across in the video before muffler modding is how difficult in that size timber to keep the saw running in its sweet spot. Only the slightest extra pressure and it would bog down. Basically a very fine margin between cutting efficiently and bogging down/stalling. I had been using the saw to earlier that day on smaller diameter timber and it was cutting perfectly fine and it didn't do to bad felling the test tree. 

The chain may not have been 100% but Vince and I both determined it was more than adequate for back to back testing. 

After the MM there was noticeable difference in terms of the amount of pressure required to bog the saw down. The margin between efficient cutting and bogging down was significantly greater. By know means could I bury the saw like Vince was doing but it was cutting much easier. In fact we did a test run before the final muffler mod video so I could get a used to the new found torque and power. 

Overall I'm very happy with the outcome and it still appeared to be within the stock tuning range as I have not yet modified the mixture screws so they can turn further. 

Will be doing some more cutting over the next few months so will keep you all posted on the long term results of the MM.

The only other outcome from this testing is that maybe I really need a bigger saw for this size timber! 

Cheers

Justin


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## Jarh73 (Jul 18, 2014)

Quick update; saw has been getting quite a bit of use lately and I have been getting the tuning just right as well perfect idling, hot, cold, warm starting etc. 

Running like a dream extremely happy. 

The only negative is it uses more fuel but given the extra power it's not really a negative. 

Weather permitting I'll be cutting some hard wood around 18 inches in diameter this weekend. Looking forward to it. 

Cheers

Justin


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## VINIFIREWOOD (Jul 18, 2014)

Tho I don't have any experience with the new 291. I have done MM on a couple older 290, 029 series saws. They all responded very well and make an ok saw into a darn good saw. Only down side is more time spent refueling cuz they love the fuel after the mod.
Thumbs up!


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## clemsonfor (Jul 18, 2014)

No way a ms291 costs $999!!


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## Jarh73 (Jul 18, 2014)

clemsonfor said:


> No way a ms291 costs $999!!


Actually the price is $1,059 list price!!!

In Australia that is. The majority of our saws are German made too so they possibly cost more to begin with. Notwithstanding Stihl Australia probably has big margins. I know the dealers don't have big margins.

Cheers

Justin


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## VinceGU05 (Jul 18, 2014)

And they are dearer again in New Zealand. [emoji37][emoji13]


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## clemsonfor (Jul 18, 2014)

Darn VAT tax will get you!!! 

Seriously what would it take for someone like me to send you a saw? Can I just ship it to your door? I have no problem doing it...even for no profit! Or if you wanna help a brother out id take donations!!


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## 7sleeper (Jul 19, 2014)

In Austria the 291 list price is 799€ ~ 1080$! And we live right next to Germany! 

7


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## Rockjock (Jul 19, 2014)

7sleeper said:


> In Austria the 291 list price is 799€ ~ 1080$! And we live right next to Germany!
> 
> 7



659€ with a 37 cm bar and chain 
671€ with a 40 cm bar and chain 

619 CAD here in Ontario ( 425€ ) Deutsch gemacht


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## Jarh73 (Jul 19, 2014)

7sleeper said:


> In Austria the 291 list price is 799€ ~ 1080$! And we live right next to Germany!
> 
> 7


Rough calculation in my head but I think you win: "The Most Expensive Stihl Saw Award"!

Cheers

Justin


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