440 mag max rpm

[blsnelling]

Im gonna do it again but yeah it was ok. My thing was if its burning all the available fuel does it any benifit any to go leaner?

Big time! A proper tune makes all the difference in the world.

 

[Boomer 87]

Im gonna wait untill my tach comes in the just see how fast it turns where i had it. Then go from there, should i change my max rpm based on having worked over the muffler?

 

[blsnelling]

Until you developed an ear for proper tuning, I'd stick with 13,000-13,500.

 

[Boomer 87]

Until you developed an ear for proper tuning, I'd stick with 13,000-13,500.

I have no qualms about ear tuning my old saws, but i admit i have a hard time with the ones like the 440 that spin that fast. How long is it safe to run a saw WOT unloaded when setting hi side? 1-2 seconds?

 

[blsnelling]

That depends on the saw, lol!

 

[Boomer 87]

O wow bad day, i try to just do it at split second intervals, but that makes it even harder to tune

 

[blsnelling]

You will be fine. That was a modified saw that someone had lightened the piston too much.

 

[blsnelling]

http://www.arboristsite.com/community/threads/chainsaw-tuning-101.250802/

 

[Boomer 87]

I watched the video of the 440, i could definately hear it going in and out if 4 stroking during the first cut. However i myself would of just went a smidge leaner untill it quit going in and out if 4 stroking. I heard you go way lean then come back some. So i guess last question is if the saw has any 4 stroking at WOT at all,will it be enough fuel no matter the load.

 

[Boomer 87]

I spent some more time with it after work today i think im closer than what i thought. I started way heavy and slowly kept comong up in rpm untill the four stroking went away under load then gave it a couple short WOT pulls, i beleive its pretty close to 13k. What i thpught was 4 stroking was actually just the exhaust note through the open front cover. I will still sideline it untill i have my tach just for assurance reasons. Afterall i got 60 other saws i can use lol

 

[Boomer 87]

Thanks to all for bearing with me as i figure it out, im not stupid but not a chainsaw expert either.

 

[Boomer 87]

One other thing i noticed while tuning the 440, i turned the high side needle in until lightly seated. And pinned the throttle and it didnt bog or die it actually wound up. Is there a hi side governor or do i have an issue. I would of thought it would of bogged and died. Right now it likes about 1.5 turns out

 

[Boomer 87]

Got my tach today!!!! Gonna be taching the hell outta everything in sight lol

 

[super3]

One other thing i noticed while tuning the 440, i turned the high side needle in until lightly seated. And pinned the throttle and it didnt bog or die it actually wound up.

Why would you even think about doing that?

 

[Boomer 87]

I just did it for a split second to make sure it would die off.

 

[Boomer 87]

I was having a hard time getting it in tune so i seated the needle at went to start over, i hit the throttle expecting it to die, so i knew it wasnt pulling fuel from somewhere else, but it reacted other than what i thought, so it may be pulling fuel from elsewhere.

 

[blsnelling]

WOT fuel is the sum of the idle circuit (L needle), a fixed main jet, and the fuel supplied through the H needle. You only shut off one of those.

 

[Boomer 87]

Ok makes sense, i can rebuild a carb fine, but i really dont know exactly whats going on inside. Thanks

 

[Boomer 87]

Thats why im here, to learn as much as possible from anyone whose willing to teach me something

 

[Boomer 87]

By god i wasnt far off with the old ear, put the tach on it and got 12,780 rpms