Muffler Modifications?

AJLOGGER · Nov 18, 2002

HI, I have a Stihl 044, 025, and a MS310. I have heard you can open up the muffler port holes on the newer models to make them run better and cooler. I would like to do this on my 044 and 025 I do not know if I want to do it on the 310. My question is how do I do this? Is it easy? And if anyone can tell me maybe you can supply a drawing or diagram to illustrate what needs to be opened up. My dad owns a machine shop with mills, lathes etc. so I have the tools I just need a little guidence if it is a fairly easy project. Also I don't want to ruin my saws so if there is a chance of this I may pass, I just need some opinions.

Thanks
ANDY:blob5:

woodsjunkie · Nov 18, 2002

I would use the search button at the top right corner...
You will find more info than you may want to read
Good luck

treeclimber165 · Nov 18, 2002

Basically you want to relieve the restrictive areas of the muffler. The outlet hole is the biggest culprit. Most new saws have an outlet hole of 3/8" or less. Open it up as much as 125% of the exhaust port size, although I've had good luck keeping it 80%-90% of the exhaust port size. If your muffler has baffles inside, they can be relieved a lot. Most older saws had NO baffles in the muffler, so you can cut away as much of the baffles as you please in most cases. Then you want to match up the muffler and gasket to the exhaust port. Many times there will be a lip to obstruct smooth flow of exhaust into the muffler. Mark the gasket and muffler, then remove it to resize it. Keep all your filings away from the exhaust port and clean thoroughly before reassembling. Metal shavings can play havoc on your piston.

Reassemble and let 'er rip!