MS260 Muffler Opening - Burnt Knuckle!

[logbutcher]

Opened the MS260 muffler--per the advice here. Two 1/4" holes on either side of the center 3/16" hole. The little 260 worked fine, big difference...
Anyone with a pic or diagram or specific measurements for this?
Do the opening holes go thru the outer baffle behind the screen ?
Must have screwed something up since the heat melted part of the 'plastic' over the top of the muffler, burnt a hole in my glove, singed the third knuckle on my left hand . Fun. All this in the middle of a felling bore thru a 24" maple.
So: any way to recover this muffler and do it right? :bang:
Right in the middle of doing the winter TSI , some sawlogs and pulp, and firewood for next winter. Help.

 

[bwalker]

The holes should be above and below the existing hole. If I remember right you also have to clean out the area behingd the heat shield on the muffler cover.

 

[bwalker]

The best way to mod it weld up the stock hole, then out a pipe on it like this.
http://www.arboristsite.com/attachment.php?attachmentid=14439&d=1090375603
http://www.arboristsite.com/attachment.php?attachmentid=13059&d=1085517856
Thats way the exhaust isnt blwing directly at the bar, engine case area.

 

[Lakeside53]

If you melted the top shroud, you are running way too lean... Also, make sure you have the reflective tape in place UNDER the shroud area above the muffler.

 

[logbutcher]

OK, Now What ?

1/4" holes are on both sides of the original vent hole, so now there are 3 openings. Do the holes go thru the outside muffler baffle behind the screen ?
I'll adjust the carb to more rich. Why does the leaning heat the thing up ?
Prefer no pipes .....just another part to get in the way .
Stil: any one with a diagram or pic to show the inside hole or holes?
Thanks.

 

[GregHarrison]

Being new to this site I read with great enthusiasm the post on relieving the exhaust. Not knowing the proper way to go about it, here is what I did. Hope I did not screw anything up.
I disasssembled the muffler. Separated the 2 pieces and removed the screen. Then I took a Dremel tool and removed the raised area around the little exhaust hole.This area is about 2 times the size of the original hole. It is the area under the little baffle and under the screen that I got rid of.
The exhaust note is much different and I did need to readjust the High speed screw out about 1/16th of a turn to get the burble back at unloaded high speed operation.
Seems to be noticeably stronger. Only cut some rich pine I found laying around but I think I can tell a considerable difference. Anyone care to guess how much power is increased by this mod?
Thanks in advance
GregH

 

[logbutcher]

Big Red Face

Burnt shroud and knuckles solved. It's a "duh" :bang: .
There's a lip on the upper face of the muffler that MUST be fitted into a female lip :censored: . I reassembled the muffler wrong. Wrong. The ass'y acts like a hinge.
.
Good that I'm not gun cleaning. It's a C.R.S. moment.
Now to get the carb adjusted correctly. Whew.