Please critique my muffler mod (MS290)

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My Ms290 muffler mod

Runs great, I removed the limiter caps, and the retainer, that Stihl claims is a part of the carburetor. I cannot get that piece, but I did get new screwcaps, did not replace any of that. Did not modify the deflector place, but I did replace the screen. Drilled 1 big hole in the dimple, (center), and 4 smaller one's, around the perimeter.
 
Here another MS 390 MM

001.jpg
 
I modded my 390 & it made all the difference, like two different saws. Haven't done the 029 yet & probably won't because it has 4 ports stock and runs great as is. It's the reason I modded my 390. The old 029 would out cut the new 390. Not any more.
 
Your MS290 has 56.5 cc. When you decide you want a REAL chainsaw that's the same 56.5 cc but much lighter and more powerful AND possible less $$$ get your self an 034. It will make you REAL happy!!:cool2:
 
Did you have to pull out your limiter caps to get it tuned properly?

Since the mod will allow more air to exhaust through the muffler the fuel mixture for the carb will need adjusted more beyond factory setting to balance with the increased air flow.
 
Hey I know this is an old post but can someone "try" to explain "4 cycling" to me as referenced in this post. Thank you immensely.
 
Your MS290 has 56.5 cc. When you decide you want a REAL chainsaw that's the same 56.5 cc but much lighter and more powerful AND possible less $$$ get your self an 034. It will make you REAL happy!!:cool2:
Yep I agree! I have a 034 and LOVE it! Kills my dads MS290! IMO 034's are solid reliable older saws that are excellent for firewood cutting and easy on the wallet for a used unit.
 
This is a good video by a fellow member

Listen to the difference in sound between WOT and loaded(sound it makes when cutting) someone else probably has better words to describe it, but the video should have what your looking for.
 
Yeah that's a big help Cory. Thank you. It's definitely gonna take some practice and trial and error but I think that will help me tune my own saws a little more accurately than I have been. It sure is just a subtle difference! Thx again.
 
Yeah that's a big help Cory. Thank you. It's definitely gonna take some practice and trial and error but I think that will help me tune my own saws a little more accurately than I have been. It sure is just a subtle difference! Thx again.
Read up more before tuning; some saws have limiting coils. The sound of a limiter can be hard to distinguish from four stroking. Best bet is to start rich( heavy four stroking) and then work lean like the video depicts. Better rich than lean. If your saw is to rich you will find it four stroking more often than not. You'll want to tune in the cut.
 
I have a Makita 6421 and the carb adjusters are epoxyed . How do you get them cleaned out ?
Hard work!!! Mine were not epoxied. Just had plugs in holes preventing adjustment. They are easy to get off. Just cut the flange on the back of the plug off and it will slide out. I've seen threads here with info on scraping out the epoxy. I haven't had to do that. Probably just have to scrape at it a while. Maybe you should ask in a new thread. Try to use the search function first. This muffler mod thread probably won't get a lot of attention. I've seen mention of using a soldering iron
 

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