saw rpm speed what the !

[minesmoria]

I have husky 359 with  walkerized muffler, specs say to run at 13500 rpm i been told  that i should now turn speed up to 14000 and others say turn it down to say 13200 or 13000.

So what should i do leave it at 13500 or what i have techometer to check speed.

[Rocky_J]

Opening up the muffler (or bolting on a modified muffler) will allow increased airflow through the motor. If you don't adjust the carb, you will most likely be running too lean. This is because you have more airflow for the same amount of fuel. A lean condition will cause the unloaded WOT rpm's to spike. I'd richen it up enough to bring the WOT rpm's back to 13,500.

[fishhuntcutwood]

This is where learning to tune a saw by ear comes in.  By opening the muffler, you've done as Rocky_J said, and have allowed more air through the saw, but by doing that you've also widened the powerband, and allowed the saw to run a bit faster and cooler.  If 13,500 rpm is the factory spec RPM with the stock muffler outlet, you've now taken the saw out of factory performance level.   So you need to adjust the rpm accordingly.  Madsen's has a pretty good tutorial on tuning a saw by ear.  Basically most think of it in a nutshell as: get your L and LA screw adjusted to get your saw running happily at idle (described on Madsen's page).  Then run your saw WOT and adjust your H screw to the lean side (turning it in) until the saw gives you the tell-tale signs it's too lean, then back the screw out to richen it up to find the rich threshhold, which is the saw "four stroking" at WOT under no load.  This bring the saw right into it's happy powerband in the cut.  That said, each saw is different.  Your opened rpms may be only a few hundred more than stock, or they may be a bit more.  And this is where a tach can help.  It's nice to be able to check your work.  Get your saw all tuned up by ear, and then run it WOT with a tach to make sure you aren't running wild at 16,000 rpm.

Madsen's says to check the WOT speed with a tach, and gives max rpm numbers, but mind you, those are stock numbers with stock mufflers, and they can't be telling customers in open forum to open up saws and run them several hundred rpms faster than the manufacturer recommends.

Here's the link-

http://www.madsens1.com/sawtune.htm

Hopefully someone can get on here and perhaps elaborate on what I've said and have it make more sense...

Jeff

[minesmoria]

I will leave it at 13500 rpm as per factory specs this should run good.

[TexasTimbers]

This is where learning to tune a saw by ear comes in.  By opening the muffler, you've done as Rocky_J said, and have allowed more air through the saw, but by doing that you've also widened the powerband, and allowed the saw to run a bit faster and cooler.  If 13,500 rpm is the factory spec RPM with the stock muffler outlet, you've now taken the saw out of factory performance level.   So you need to adjust the rpm accordingly.  Madsen's has a pretty good tutorial on tuning a saw by ear.  Basically most think of it in a nutshell as: get your L and LA screw adjusted to get your saw running happily at idle (described on Madsen's page).  Then run your saw WOT and adjust your H screw to the lean side (turning it in) until the saw gives you the tell-tale signs it's too lean, then back the screw out to richen it up to find the rich threshhold, which is the saw "four stroking" at WOT under no load.  This bring the saw right into it's happy powerband in the cut.  That said, each saw is different.  Your opened rpms may be only a few hundred more than stock, or they may be a bit more.  And this is where a tach can help.  It's nice to be able to check your work.  Get your saw all tuned up by ear, and then run it WOT with a tach to make sure you aren't running wild at 16,000 rpm.

Madsen's says to check the WOT speed with a tach, and gives max rpm numbers, but mind you, those are stock numbers with stock mufflers, and they can't be telling customers in open forum to open up saws and run them several hundred rpms faster than the manufacturer recommends.

Here's the link-

http://www.madsens1.com/sawtune.htm

Hopefully someone can get on here and perhaps elaborate on what I've said and have it make more sense...

Jeff

Hopefully someone can get on here and perhaps elaborate on what I've said and have it make more sense...

I don't know ... you did a pretty good job! You described exactly the type of informationI was looking for in a post I had made the previous day "Opening Up The Muffler". I missed this thread somehow.
I never did open it up because I was didn't know what I was doing. I still don't but I want more power out of both saws. Yesterday i was cutting into a big Mulberry I'd had lying around for 3 months to get it small enough to get on the mill and my 372XP was bogging down going through that behemoth parallel to the grain and burying the 32" bar, and I got to thinking about that post I'd made asking about opening up the muffler on my Stihl 025 . I think I want to do it on both saws now. I printed off the Madsen's refernece you made. Thanks.

[Ever Green]

When I took GOL 1 and 2 we were taught to ...see if I get this right---when tuning make sure saw is warmed up and then run wide open...tune High adjustment in "till she screams and and back it out "till she flutters...in till she screams out till she flutters...did I get that right?

[sawguy21]

Sounds good to me for the older saws. Some of the newer ones are getting rev limiters that will cause them to 'flutter' even when too lean so a tach becomes critical.