The official saw tuning thread.

[ShoerFast]

Just .02 cents worth to finding that low-end sweet-spot.

As Andy mentioned, weak clutch-springs will toss this procedure out the window.

It seems that a when a lot of people are having a bad idle day, the first thing they do is adjust the speed screw, or butterfly screw. The position of the throttle plate or butterfly valve, has a lot to do with how the saw will accelerate, if the plate has been advanced into the transfer slot for idle speed or to fix a stalling on deaccelaration , or compensating for a carb that needs a rebuild, they don't seem to accelerate as well, are sluggist and will not fallow the trigger as well.

After a carb rebuild, or to find that sweet spot again, let the saw warm up well, then let it idle for a minute or so on it's belly. Pick the saw up and roll it to one side or the other, even carefully flip it upside down, what your going to listen for is the saw stumbling rich with extra gas that has built up in the crank. There should be very little, or no change regardless of attitude.

If the saw fails a roll-out test, try leaning the "L" screw, if this pick up speed, and the clutch engages and the chain creeps, back the speed screw out and repeat the roll out test.

repeating this till your not getting any change rolling the saw after idling for a time, when you can get the chain to creep at will by leaning and riching the "L" screw, and a crisp acceleration, no stall at deaccelaration your there, never touch the speed screw again, unless your ready to repeat the roll out test again.

As we know that every saw is different, what I think happens with saws running on the transfer slot is the transfer slot is a very course/rich fuel for idle, and droplets fall out , build up, and cause stumbling problems. Getting that throttle valve just at the edge, or very slightly into the transfer slot gives a much smoother idle, and fastest trigger/acceleration.

 

[stihl 440]

hardwood

28 isn't realy "long" for a 440. I'd say 20 is short, 32 is long and 25/28 are somewhere in the middle.

Best way to tune is to get it about right, then weak with timed cuts. Or, if you can't be bothered about he last few % and be worried about day to day changes, err solidly on the rich side and just cut wood.

Just remember lakeside I'm on the east coast. We have all hardwood over here,(we have some softwood, but most of the time nobody wants to mess with it). We cut some pine, but that depends on how limby it is, if it is limby them we leave that for the guys with the timbco track harvesters not fellerbunchers. Because the guys with the fellerbunchers don't like it either, because they still have to limb it sometime. But we do sometimes get a pine stand that isn't too limby. The only softwood here that pays good is hemlock, and white pine. It is very rare over here to see over a 20" bar on a saw that is 440 size. Only the saws that are like, 660's size and over have 24" on them.

 

[Haywire Haywood]

I have a question concerning tuning and elevation/atmospheric conditions.

If a saw's sweet spot is 14k at 5000ft, will it still be in tune if readjusted to 14k at 1000ft.

The point of my question I guess is this. I'm not much good at tuning. If at the GTG the guys tweak my saws just so, can I simply check the rpm with a tach and reset it to that when I'm cutting back home?

Ian

 

[Freakingstang]

Just remember lakeside I'm on the east coast. We have all hardwood over here. It is very rare over here to see over a 20" bar on a saw that is 440 size. Only the saws that are like, 660's size and over have 24" on them.

Yup, Standard logger saw in this area are 460's with 20" and most 660's run a 20" too. Every once in a while there are 660's with 24", but 20" is bar far the norm. People look at me funny when i break out the 066 with a 36 incher...

 

[rahtreelimbs]

I have a question concerning tuning and elevation/atmospheric conditions.

If a saw's sweet spot is 14k at 5000ft, will it still be in tune if readjusted to 14k at 1000ft.

The point of my question is this. I'm not much good at tuning. If at the GTG the guys tweak my saws just so, can I simply check the rpm with a tach and reset it to that when I'm cutting back home?

Ian

FWIW...........not that I am an authority on this...........at the GTG's that I have gone to I ran a modded 359 and 372. I turned them up to 14'600 rpm's just for the GTG and re-adjusted them back to 13'800 rpm's ( the sweet spot for work ) when I get back!!!

 

[ShoerFast]

I have a question concerning tuning and elevation/atmospheric conditions.

If a saw's sweet spot is 14k at 5000ft, will it still be in tune if readjusted to 14k at 1000ft.

The point of my question I guess is this. I'm not much good at tuning. If at the GTG the guys tweak my saws just so, can I simply check the rpm with a tach and reset it to that when I'm cutting back home?

Ian

Ian

My .02 cents here is no.

The way I understand it is your setting the air : fuel ratio, optimal or sweet spot at 14K @ 5000' would be something lower at 1000' , not a lot, maybe 300 - 500 rpm's slower would be the same ratio.

An easy way to check that would be to check were the burble is at 5000' , for a say, say that is is at 13,500 , the sweet spot would be burble +500 rpm's, (burble , then lean 500rpm's) ,,, for the 2 cents, my bet would be that your 1000' burble would be at 13,000rpm's? (give or take)

 

[Haywire Haywood]

That's my problem, I hear no burble, no 4 stroking. All I hear is WAAAAAAAAA when I hold the trigger down. Madsen's audio doesn't help either, it just sounds like a wide open chainsaw to me. Frustrating it is.

Ian

 

[royta]

All I hear is WAAAAAAAAA when I hold the trigger down.

I put a transmission in mine. All I hear is WAAAAAAAAAAA WAAAAAAAAAAAA WAAAAAAAAAAAAAAA WAAAAAAAAAAAAAAA

It's awesome.

 

[ShoerFast]

That's my problem, I hear no burble, no 4 stroking. All I hear is WAAAAAAAAA when I hold the trigger down. Madsen's audio doesn't help either, it just sounds like a wide open chainsaw to me. Frustrating it is.

Ian

Yes, Tach time, starting at what, $20 bucks?

Back to your question, I live at about 6000" , but do a lot of cutting around the 9000" mark. At home setting my MS-660 at 13K just barely berbles out of the wood, but clears in the wood and is a good timed cut. Bring it to alititude, 9000' and it burbles at closer to 13,300 rpm's and clears in the wood.

 

[Lakeside53]

Just remember lakeside I'm on the east coast. We have all hardwood over here,(we have some softwood, but most of the time nobody wants to mess with it). We cut some pine, but that depends on how limby it is, if it is limby them we leave that for the guys with the timbco track harvesters not fellerbunchers. Because the guys with the fellerbunchers don't like it either, because they still have to limb it sometime. But we do sometimes get a pine stand that isn't too limby. The only softwood here that pays good is hemlock, and white pine. It is very rare over here to see over a 20" bar on a saw that is 440 size. Only the saws that are like, 660's size and over have 24" on them.

I know about your wood.. I'm taking about tuning.... WOT on a 440 with 20 inch will be rich at the max rpm allowed...

 

[Lakeside53]

That's my problem, I hear no burble, no 4 stroking. All I hear is WAAAAAAAAA when I hold the trigger down. Madsen's audio doesn't help either, it just sounds like a wide open chainsaw to me. Frustrating it is.

Ian

TACH

 

[Lakeside53]

I have a question concerning tuning and elevation/atmospheric conditions.

If a saw's sweet spot is 14k at 5000ft, will it still be in tune if readjusted to 14k at 1000ft.

The point of my question I guess is this. I'm not much good at tuning. If at the GTG the guys tweak my saws just so, can I simply check the rpm with a tach and reset it to that when I'm cutting back home?

Ian

It will be close enough...

 

[stihl 440]

rich?

I know about your wood.. I'm taking about tuning.... WOT on a 440 with 20 inch will be rich at the max rpm allowed...

So, you're saying a 440 with a 20" will be rich at 13,500? I run mine at 13,900. :biggrinbounce2:

 

[Lakeside53]

Yep... but it's o.k. if YOU control the max rpm... WOT is a lowsy way to tune, particularly on big saws with short bars.

 

[ShoerFast]

Andy

Any tricks without a tach on a 361?

I did cut the metal or raised area around the 5/16 - 3/8th exit hole to give is a healthy 5/8" hole or so.

Running that saw first time today was simply amazine, everything is a fast cut! But it seems a real trick to get anything better then ball park.

I have noticed that every bet of gas rich seems to give it an occasional jurk or berble, and keeps getting more burbely as you progress the "H" jet.

(interesting note, they were ready to send me out the door when I asked if I could see it on tach, just to get a feel for the tone brake, they were happy to,,,,, it was at 17K "H" against the rich stop!,,,,, we cut the stops off)

 

[Haywire Haywood]

TACH

It will be close enough...

Good to know. I have the SenDEC STS-5000 tach that Bailey's sells. http://store.baileys-online.com/cgi-bin/baileys/1112?mv_session_id=KJF9QypE&product_sku=17122

Ian

 

[Lakeside53]

Andy

Any tricks without a tach on a 361?

I did cut the metal or raised area around the 5/16 - 3/8th exit hole to give is a healthy 5/8" hole or so.

Running that saw first time today was simply amazine, everything is a fast cut! But it seems a real trick to get anything better then ball park.

I have noticed that every bet of gas rich seems to give it an occasional jurk or berble, and keeps getting more burbely as you progress the "H" jet.

(interesting note, they were ready to send me out the door when I asked if I could see it on tach, just to get a feel for the tone brake, they were happy to,,,,, it was at 17K "H" against the rich stop!,,,,, we cut the stops off)

Nope... I'm useless tuning a stock muffler 361 without a tach. NO real burble at all.

Unless the muffler has been gutted on the inside, cutting the exit hole will have zero effect on the muffler output.. It's fed though a long tiny tube... unless you actually cut that tube away too, and that will negate your spark arrester. I add a second 16mm port and leave the factory port alone. Maybe I'm confused with what you did.


I assume you looked at this thread showing the muffler internals?

http://arboristsite.com/showthread.php?t=33528

 

[PWB]

So............. My 084 with 30" bar @ 12,500 that sounds too rich to me? (non rev limited coil) I'm chicken to go any faster.......... I'm at about 1000 feet.

Bought the stihl edt 8 a few months ago.

 

[stihl 440]

12,500

So............. My 084 with 30" bar @ 12,500 that sounds too rich to me? (non rev limited coil) I'm chicken to go any faster.......... I'm at about 1000 feet.

Bought the stihl edt 8 a few months ago.

I think 12,500 is the stock max RECCOMENDED RPM for a 084. That saw isn't desined to turn RPMS but it is designed for torque, and long bars. I don't know of anybody tuning them higher, and I don't have one YET to tell you. But I think lakeside has messed with 084's before, he will probably know. :hmm3grin2orange: :greenchainsaw:

 

[Gypo Logger]

I think carb adj. is where alot of people go wrong with a saw.
I know some local loggers who equate out of wood rpm with power, however, fuel requirements are alot different in the wood than out.
They were always going for max rpm out of the wood and wondered why they were losing bottom ends out of 088's and 066's.
Over the years I have developed my own method of carb adjustment.
Given that the carb has good diaphrams and the filtre is clean, I first turn up the idle speed screw (LA) till the chain begins to turn, then I turn in or out the L to get the highest idle rpm where the chain is turning the fastest, then I turn out the L about 5 minutes or so. If the saw then responds fast to full throttle I leave it there and turn out the LA till the chain just stops turning.
Then I go to the H and find the highest audible rpm and then richen it out about 5 minutes till it's not a flat out scream, but a slight burble.
This procedure I repeat at least two times till I get it right. Don't forget the 32:1.

John