# How do I Muffler Mod my chainsaw? Help



## TKeshishian (May 18, 2011)

I bought a 50cc Craftsman chainsaw with a 20" bar recently. I am actually pretty impressed with the saw. I've been through 10+ cords of wood and the only thing I've done is put a skip tooth chain on it. It cuts great but have heard that doing a muffler mod would increase my power. I am quite versed in adjusting carbs so I understand that if the muffler has better flow, the carb needs to be tuned as to not go too lean. I've heard of people just basically doubling the amount of holes in the muffler all the way to adding welded in pipes. I would be more inclined to do the less obvious mod. Any help on how to go about this would be really great. I called sears/craftsman and the the motor/drivetrain is a husqvarna 50.2cc which is the same as a husqvarna 450. Thanks in advance for the help.


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## HILLBILLYREDNEC (May 18, 2011)

*Muff Mod*

You can start with 2 3/8" hole then see how it is performing, may need to open up the internal baffle a bit as well:msp_thumbup:


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## Anthony_Va. (May 18, 2011)

No use in making an extra hole on most stock saws. Just open the existing hole up to maybe 5/8"-3/4" and take out the internal baffles. That way it will still look stock but run alot better. 
If you want another hole, cut two slits in the side of the muffler about 1/4" apart and 1" tall and pry them open with a screwdriver, making them into vents. There's pictures of a 361 muffler like that on here somewheres. I'll take a pic of mine tomorrow if you don't find it by then.


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## TKeshishian (May 18, 2011)

Anthony_Va. said:


> No use in making an extra hole on most stock saws. Just open the existing hole up to maybe 5/8"-3/4" and take out the internal baffles. That way it will still look stock but run alot better.
> If you want another hole, cut two slits in the side of the muffler about 1/4" apart and 1" tall and pry them open with a screwdriver, making them into vents. There's pictures of a 361 muffler like that on here somewheres. I'll take a pic of mine tomorrow if you don't find it by then.


 
Thanks. That sounds like what I'm probably going to do. I'm assuming this is going to make it run leaner correct?


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## Anthony_Va. (May 18, 2011)

TKeshishian said:


> Thanks. That sounds like what I'm probably going to do. I'm assuming this is going to make it run leaner correct?


 
Usually so. But I have seen some that don't even need to be tuned. Most will need to be richened though. If you post pics of your muffler, we could tell you more of what you need to do. Pics inside and out would help.


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## TKeshishian (May 18, 2011)

Anthony_Va. said:


> Usually so. But I have seen some that don't even need to be tuned. Most will need to be richened though. If you post pics of your muffler, we could tell you more of what you need to do. Pics inside and out would help.


 
I will post pics tomorrow. Thanks for your help already.


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## Hank Chinaski (May 18, 2011)

HILLBILLYREDNEC said:


> You can start with 2 3/8" hole then see how it is performing, may need to open up the internal baffle a bit as well:msp_thumbup:


 
there's a lot of difference in a single 2 and 3/8" hole and two 3/8" holes... yes, punctuation makes a lot of difference sometimes.

and you didn't bother mentioning about the carb adjustment necessary no matter what the muffler mod is....

How many muffler mods have you done on a craftsman? What are you basing your advice on?


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## TKeshishian (May 18, 2011)

Anthony_Va. said:


> Usually so. But I have seen some that don't even need to be tuned. Most will need to be richened though. If you post pics of your muffler, we could tell you more of what you need to do. Pics inside and out would help.


 
Here's a stock picture of the saw and a link to the sears outlet website that is now selling it. I'm assuming they discontinued as it's no longer available on the sears website. 
Craftsman 50 cc Gas Chain Saw : Sears Outlet


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## TKeshishian (May 19, 2011)

:angry2::greenchainsaw::help:


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## Bowtie (May 19, 2011)

Number 37 said:


> there's a lot of difference in a single 2 and 3/8" hole and two 3/8" holes... yes, punctuation makes a lot of difference sometimes.
> 
> and you didn't bother mentioning about the carb adjustment necessary no matter what the muffler mod is....
> 
> How many muffler mods have you done on a craftsman? What are you basing your advice on?


 
All I read was advice on what he thought, never said he had hardcore facts. Jeeze, chill out newbie...


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## TKeshishian (May 19, 2011)

*Here's the actual muffler pics*



Anthony_Va. said:


> Usually so. But I have seen some that don't even need to be tuned. Most will need to be richened though. If you post pics of your muffler, we could tell you more of what you need to do. Pics inside and out would help.



The muffler is actually completely hollow. No baffling or anything. Just a hole under the spark arrestor screen that goes on top and exhausts through the little scoop.

View attachment 184578
View attachment 184579


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## Anthony_Va. (May 19, 2011)

That one will be easy. Just pull the screen out and open up that hole. I'd probably open up to about 3/4". Then just put the screen back ni a tune the carb.


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## TKeshishian (May 19, 2011)

Anthony_Va. said:


> That one will be easy. Just pull the screen out and open up that hole. I'd probably open up to about 3/4". Then just put the screen back ni a tune the carb.


 
That's exactly what I was thinking of doing but wanted to hear it from someone else first. Thanks for the help Anthony.


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## TKeshishian (May 25, 2011)

Anthony_Va. said:


> That one will be easy. Just pull the screen out and open up that hole. I'd probably open up to about 3/4". Then just put the screen back ni a tune the carb.


 
So I made the whole about 3/4". Not the prettiest hole but hey. Sounds a little bit louder now and noticable high end power. Had to order a craftsman chainsaw carb tool as the adjustment knobs are not slotted. Anyways after tuning the carb high and low, this thing screams. Probably a lot of people wouldn't think anything of my craftman but with a skiptooth, it beats my buddy's stock 455 rancher through wood. And I'm noticing it is running cooler as well. Thanks a lot for the advice Anthony.


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## CTYank (May 25, 2011)

TKeshishian said:


> That's exactly what I was thinking of doing but wanted to hear it from someone else first. Thanks for the help Anthony.


 
Don't throw the screen away. It's a spark-arrestor, required in states like Maine, and in many state and federal forests. Easy guess why. :msp_rolleyes:


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## Nitroman (May 25, 2011)

Anthony_Va. said:


> That one will be easy. Just pull the screen out and open up that hole. I'd probably open up to about 3/4". Then just put the screen back ni a tune the carb.



Bingo. See how easy it is? Now you'll need to buy porting tools and port that puppy, then there'll be new threads about what carbs can interchange so you can go bigger on the carbs, and pipes...it'll never end..:msp_w00t:


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## James Sawyer (Jan 23, 2019)

I have Stihl 034 AV I'm upgrading to a 48mm ported bigger bore cylinder. I'm installing a 036 muffler which is what on stock stihl with a 48mm cylinder. If I match the cylinder exhaust to inlet open area of the 036 exhaust gasket it calculates out to 615mm sq. , the open area of the baffles within the muffler which is 325.8mm sq . The stock muffler outlet is 201.06mm sq. If I use the 80% rule I need to open up the baffles to at least >492mm sq and the muffler outlet to 492mm. I'm assuming the baffles should be open greater than 492mm sq. As I read this thread is that correct to achieve the proper back pressure?


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## Rick Stephens (Jan 23, 2019)

Perfect place to post your first - an 8 year old thread.


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## James Miller (Jan 23, 2019)

James Sawyer said:


> I have Stihl 034 AV I'm upgrading to a 48mm ported bigger bore cylinder. I'm installing a 036 muffler which is what on stock stihl with a 48mm cylinder. If I match the cylinder exhaust to inlet open area of the 036 exhaust gasket it calculates out to 615mm sq. , the open area of the baffles within the muffler which is 325.8mm sq . The stock muffler outlet is 201.06mm sq. If I use the 80% rule I need to open up the baffles to at least >492mm sq and the muffler outlet to 492mm. I'm assuming the baffles should be open greater than 492mm sq. As I read this thread is that correct to achieve the proper back pressure?


Try starting a new thread to get your question answered.


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## 1Alpha1 (Jan 23, 2019)

I wonder if he ever got his muffler modded?


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