The official saw tuning thread.

I think we need a official saw tuning thread. I need to know how to tune my saws. I haven't been able to get a straight answer out of my dealer or my manuals. I did a search, but I still can't understand it. Like I think the LS screw is idle, right? And the L screw is for the saw comming off idle, manual says to tune it so it accelerates smoothly. And the H screw is for the max high speed RPM, right? And how do you ear tune? Do you tune it until the saw is 4 stroking then back off some or what? I've hear all sorts of stuff and I don't know what to do. This might sound stupid but, I want to know how to tune.:help: This is the only thing that I don't know how to do on a saw. I think some of the :newbie: 's can use this thread also. I want to get a tach soon. I only know that my 440 and 460 are running at 13,900 because my dealer tuned them with a tach. :help::hmm3grin2orange: :biggrinbounce2:

I agree. Get a detailed report and sticky it at the top.

Here's a link to Madsen's saw tuning page. There are audio files to help learning to tune by ear.



http://web.archive.org/web/20051228040631/www.madsens1.com/sawtune.htm

A tach is your best bet. I've tuned by ear but invested in a tach. It gives me piece of mind knowing exactly what RPM the saw is running, instead of "that's close". My saws are tuned to 200-300 RPM's beyond the manufacturers MAX. recommendation. Some people go as far as 500 beyond MAX.

After reading posts over the last few days, I ordered me a tach from my Stihl Dealer. It should be here tomorrow.
Once I get it, I'm looking at a muffler mod and carb setting for my 036
John

I always tune "by ear" and then recheck with a tach. This also gives me an rpm to shoot for the next time the saw is worked on!!!

jack-the-ripper said:

A tach is your best bet. I've tuned by ear but invested in a tach. It gives me piece of mind knowing exactly what RPM the saw is running, instead of "that's close". My saws are tuned to 200-300 RPM's beyond the manufacturers MAX. recommendation. Some people go as far as 500 beyond MAX.

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I agree, I always tend to de-tune a saw a bit by ear. I guess I'm just cautious. When I have a saw tuned on a tach It's usually set faster than I would by ear.

wow!

troutfisher said:

Here's a link to Madsen's saw tuning page. There are audio files to help learning to tune by ear.



http://web.archive.org/web/20051228040631/www.madsens1.com/sawtune.htm

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Wow troutfisher, that helped a lot! All the time I spent on madesens wedsite, I never saw that. But I could still use more info. :hmm3grin2orange: :biggrinbounce2:

rahtreelimbs said:

I always tune "by ear" and then recheck with a tach. This also gives me an rpm to shoot for the next time the saw is worked on!!!

Click to expand...

+1.



LS (or LA) is just a throttle preset - nothing to do with mixture. L is the low speed mixture, and H is the high speed mixture.

After you are "in tune" with your saw, you won't need the tach, but it takes a while to train the ear. Some saws are very difficult to tune by ear - like a 361 - you don't ever get a "burble" - just a change of tone. Easier after a muffler mod though..


It's important to remember that the WOT methods are only a crude approximation of correct mixture. It will overstate the mixture on short bars (too rich - to keep RPM down) and understate (too lean) on very long bars (leaning out to get to max rpm). There is only one correct H speed mixture for a given set of environmental conditions.


The low end tuning is harder for some people than the H end - often because they are chasing weak clutch springs.

Lakeside53 said:

+1.



LS (or LA) is just a throttle preset - nothing to do with mixture. L is the low speed mixture, and H is the high speed mixture.

After you are "in tune" with your saw, you won't need the tach, but it takes a while to train the ear. Some saws are very difficult to tune by ear - like a 361 - you don't ever get a "burble" - just a change of tone. Easier after a muffler mod though..


It's important to remember that the WOT methods are only a crude approximation of correct mixture. It will overstate the mixture on short bars (too rich - to keep RPM down) and understate (too lean) on very long bars (leaning out to get to max rpm). There is only one correct H speed mixture for a given set of environmental conditions.


The low end tuning is harder for some people than the H end - often because they are chasing weak clutch springs.

Click to expand...

Andy, I have a new sig for you :

" Lakeside53 tells you how it really is " :rockn:

The low end tuning is harder for some people than the H end - often because they are chasing weak clutch springs

Click to expand...

I tinker a lot on older generation saws lately and think that diagnosing and tuning the carb is the most difficult and time consuming part of the rebuilt. Low end tuning calls for some experience too, as you stated. Judging condition of membranes and their functioning is not easy also, while buying new sets is not always obvious for collector saws (they are not used for a living, hehe).
But I am getting better at it


PS. just realize this is my 1000 th post on AS. Welp, I need a beer

belgian said:

.......

PS. just realize this is my 1000 th post on AS. Welp, I need a beer

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:rockn: almost there too...

For all Stihls the manual tells you to turn them a certain number of times from completely closed. I think it is either 2and 1/2 or 1 and 1/2 and I go from there. You can do it by ear if you are familiar enough to do so. As long as you know which is open and closed, you should be all right. one is Idle, one is the Low, and one is the High. Usually the High needs very little adjustment, it's the Low that is a little touchy. Once you start fine tuning you will know when it is right, just make sure you have the saw running when you make the adjustments.

tuning

jack-the-ripper said:

A tach is your best bet. I've tuned by ear but invested in a tach. It gives me piece of mind knowing exactly what RPM the saw is running, instead of "that's close". My saws are tuned to 200-300 RPM's beyond the manufacturers MAX. recommendation. Some people go as far as 500 beyond MAX.

Click to expand...

I've alway's told my dealer to turn them 400-500 over max and never had a problem. But I started this tread because I want to start doing it myself. :greenchainsaw: :hmm3grin2orange:

Stihl's spec'ed max wot rpm is +/- 1000 rpm, but that doesn't mean you should alays err on the high side. On a long bar that a recipie for lean seize.

Lakeside53 said:

Stihl's spec'ed max wot rpm is +/- 1000 rpm, but that doesn't mean you should alays err on the high side. On a long bar that a recipie for lean seize.

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I just briefly skimmed the web archive of Madsen's instructions, and he mentions setting max speed with bar & chain removed from saw. That should eliminate the problems of a lean sieze, shouldn't it? I guess that also means that once you put your bar & chain back on, no matter how short it is, the max speed will decrease from your setting.

That way will pretty much guarantee you end up with an under performing saw (too rich). Stihl wants you to put the saw engine under some load, and that's why they spec "with bar and correctly tensioned chain".

I find it difficult to tune a saw correctly with the bar and chain removed.

Remember, its the mixture being adjusted, not the RPM. The RPM is a function of correct mixture, not the other way around. That is why the "ear" part is important (on saw that will let you do it).

Lakeside53 said:

That way will pretty much guarantee you end up with an under performing saw (too rich). Stihl wants you to put the saw engine under some load, and that's why they spec "with bar and correctly tensioned chain".

I find it difficult to tune a saw correctly with the bar and chain removed.

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You're right, I forgot about what it says in Stihl's manual.

bar

Lakeside53 said:

Stihl's spec'ed max wot rpm is +/- 1000 rpm, but that doesn't mean you should alays err on the high side. On a long bar that a recipie for lean seize.

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Ok, so my 440,460's running at 13,900 with a 20" bar is ok. I understand what you mean about the long bar rpms. So if a saw with a long bar(28" or so) on it is running 13,900, that would be the same as it running 14,500 with a 20" bar= lean seize on stock saw.

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.