MS390 really blows

[GeorgiaVOL]

Awesome thread! I'm about to put together a friend's 290 that was scored. I have an oem replacement cyl and piston. Is there much that can be done to the exhaust port or is it best just to stick with the muff mod?

 

[GeorgiaVOL]

Awesome thread! I'm about to put together a friend's 290 that was scored. I have an oem replacement cyl and piston. Is there much that can be done to the exhaust port or is it best just to stick with the muff mod?

 

[Fruecrue]

Awesome thread! I'm about to put together a friend's 290 that was scored. I have an oem replacement cyl and piston. Is there much that can be done to the exhaust port or is it best just to stick with the muff mod?

I can't definitively say either way if it makes more power, but if it's for myself or a friend I like to widen them.
If I'm selling it, I leave them alone.

 

[GeorgiaVOL]

He wants to port it a bit. I told him usually it's best just to go a little wider but not go up or down.

 

[Fruecrue]

I haven't timed many 1127 series.
I have found squish to be a very wide range, I've seen from .025"-.050".
My buddy had an AM top end, new, 125 psi compression, .070" squish.
I've heard timing also varies, I can neither confirm nor deny.

 

[Fruecrue]

He wants to port it a bit. I told him usually it's best just to go a little wider but not go up or down.

I've only widened, never changed timing.

 

[Poleman]

Just widening on the intake and exhaust along with a mugger mod really wak e s these up!!! On the other side they really wake up with slight changes in heights and transfer work really wakes them up and makes them a total sleeper!!!
This series saw is really good for a clammy.

 

[Wood Doctor]

Ever notice how the 250, 290, 310, and 390 all seemed to whine when they run? Some call it the clam shell whine. Maybe with a good muff mod they will stop whining and start growling. Just MHO.

 

[Jon1212]

Ever notice how the 250, 290, 310, and 390 all seemed to whine when they run? Some call it the clam shell whine. Maybe with a good muff mod they will stop whining and start growling. Just MHO.

Mine definitely doesn't whine....a friend I do volunteer cutting with likes using my MMWS MS390....if we are clearing a swale, or working through a meadow, I have him start on the opposite side from me. He's been bucking on the other side of a ridge and I know exactly where he is by the sound this saw makes. Even with a few other saws running.

 

[Wood Doctor]

Mine definitely doesn't whine....a friend I do volunteer cutting with likes using my MMWS MS390....if we are clearing a swale, or working through a meadow, I have him start on the opposite side from me. He's been bucking on the other side of a ridge and I know exactly where he is by the sound this saw makes. Even with a few other saws running.

Well, maybe it's not a whine. Poor choice of words on my part. I heard that comment at a GTG. It is distinctive, however, and means it's a clam shell.

 

[Jon1212]

Well, maybe it's not a whine. Poor choice of words on my part. I heard that comment at a GTG. It is distinctive, however, and means it's a clam shell.

Oh I know what you mean....

I was just saying with the way my muffler was modded, it's more like a shout.

 

[Mastermind]

Oh I know what you mean....

I was just saying with the way my muffler was modded, it's more like a shout.

Or a murderous scream.

 

[Jon1212]

Or a murderous scream.

Yes.....maniacal in fact.