Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: brettl on February 24, 2014, 09:01:54 pm

Title: 039 Muffler Mod
Post by: brettl on February 24, 2014, 09:01:54 pm
I got a 039 recently and someone has begun a muffler mod. They made the port opening big enough to get some kind of cutting tool in the muffler and have cut the baffle into pieces. Since they were all cut loose I've pulled them all out and now have an empty can. I haven't done a mm before and don't know how much should be removed, seems it would need something left for backpressure. No drilling has been done to the outside. Can you pull all of the insides out without destroying the powerband?
Title: Re: 039 Muffler Mod
Post by: 660magnum on February 25, 2014, 04:51:16 am
Yes! Most of my saws have empty can mufflers with little back pressure.
Title: Re: 039 Muffler Mod
Post by: H 2 H on February 25, 2014, 05:08:13 am
(http://i59.photobucket.com/albums/g317/H2H_PHOTOS/MS%20250/390%20MM/001.jpg)

(http://i59.photobucket.com/albums/g317/H2H_PHOTOS/MS%20250/390%20MM/DSC_9957.jpg)

(http://i59.photobucket.com/albums/g317/H2H_PHOTOS/MS%20250/390%20MM/DSC_0313.jpg)

The opening in the muffler itself is about 110% of the intake side of the muffler but the cover plate opening is about 100% of the opening
Title: Re: 039 Muffler Mod
Post by: Moparmyway on February 25, 2014, 10:55:50 am
That looks like it got real hot in there !!!
Title: Re: 039 Muffler Mod
Post by: H 2 H on February 25, 2014, 01:18:45 pm
That looks like it got real hot in there !!!

Had to heat up the crimp to take it apart

(http://i59.photobucket.com/albums/g317/H2H_PHOTOS/MS%20250/390%20MM/DSC_0319.jpg)
Title: Re: 039 Muffler Mod
Post by: Cut4fun . on February 25, 2014, 01:59:06 pm
The 30 min caveman muffler mod I did on these was good for 20% . All I did was drill  through baffle in middle to outside. Then opened and added lower holes below baffle and added holes above baffle.  Just opened and cut  the deflector alittle.  Just the way I found I liked them.

You could do just 1 bigger hole in middle of baffle. I just always did 2 smaller ones. This way no uncrimping or removing the baffle.


(http://chainsawrepair.createaforum.com/index.php?action=dlattach;topic=360.0;attach=4136;image)
(http://i59.photobucket.com/albums/g289/doemaster789/PP325/3450390025002.jpg)
Title: Re: 039 Muffler Mod
Post by: brettl on February 25, 2014, 11:26:21 pm
Awesome! Thanks for the replies. ;D Glad to see them all as I've learned from all of them and yours, Brian, looks just like mine. So glad to know mine isn't scrap.  I'm doing a CS-400 next. That muffler must weigh half a pound with all the stuff inside!! ??? Reminds me of the little Suzuki LT80 4 wheelers at the motorcycle dealership I worked at. Had 1" or so headers but a restrictor that was basically a washer with a whole just big enough to fit a pencil through. Liability reasons of course since they were for youngsters but we usually took them out, though we weren't supposed to. Thanks again for the replies.
Title: Re: 039 Muffler Mod
Post by: Bobby Charles on March 02, 2014, 11:21:33 pm
I put  dp cover on but I did not take out baffle  on a 460