Tuning saws for better performance without ear

[Dieselshawn]

Hello fellas, I’m attempting to learn to tune saws after doing modifications and using the dyno.

I am deaf and have no way to hear how a saw is tuned for best carb performance.

I’ve always had my logging friends tune the saws for me after I did the work on them.

They’re not sure how to teach me to tune the saw without hearing as that’s how they’ve always done it.

Currently I’m doing muffler work for a 390 husky and doing that on the dyno.

At the moment I’m reading spark plug colour to make sure I’m not leaning the saw.

Opening the muffler did lower the idle speed but I’m not touching the carb screws at the moment until I figure out how to return it to the original setting if the guy still wants to run the stock muffler if he doesn’t like the open muffler.

I’m open to learning here, thank you.

 

[Ketchup]

If you’re using a good Tach you’re probably pretty close. I like to get a cut started and do my final adjustments by feel as I’m cutting. I’m definitely still listening though.

 

[Dieselshawn]

ok, so I could adjust by tach alone and feel how it performs while cutting and piss revving

 

[Duane(Pa)]

Have someone help you find an appropriate number of rpm’s on the rich side of peak. I don’t know what that number might be. Guessing at least 400 maybe 600?

 

[redline4]

I'd think what the spark plug looks like along with a tach and you should be good.
The plug will tell you what you need to know and the tach will let you know your in the ballpark.

 

[Dieselshawn]

Thank you guys. Once a muffler has been modded, the saw slows down, so I should increase the rpm to 3,400 for example?

Then adjust the H screw for the larger exhaust?

 

[Ketchup]

Unfortunately idle and WOT rpm are different for every model. If you can find tuning specifications in the manual that will help a lot.

I don’t usually set the idle by Tach, so I’m not much help there. I would think it’s more like 2600-2800. Then set the H to 12500 at WOT. You may have to adjust the L a bit more afterwards for good throttle response. Then make a few cuts and adjust the H in small increments until you find the highest rpm in the cut. I tune mine just a hair more rich than max rpm. For a 390 you probably want a 20-28” log to simulate the wood the saw will actually run in. Never a bad idea to check the plug after some run time.

 

[Dieselshawn]

I do live in a small town and have no wood to cut.

One of the reasons I built the dyno.

 

[Stump Shot]

Hello fellas, I’m attempting to learn to tune saws after doing modifications and using the dyno.

I am deaf and have no way to hear how a saw is tuned for best carb performance.

I’ve always had my logging friends tune the saws for me after I did the work on them.

They’re not sure how to teach me to tune the saw without hearing as that’s how they’ve always done it.

Currently I’m doing muffler work for a 390 husky and doing that on the dyno.

At the moment I’m reading spark plug colour to make sure I’m not leaning the saw.

Opening the muffler did lower the idle speed but I’m not touching the carb screws at the moment until I figure out how to return it to the original setting if the guy still wants to run the stock muffler if he doesn’t like the open muffler.

I’m open to learning here, thank you.

A few thoughts come to mind, as suggested a tachometer should get you in the ballpark with the manufacturers recommendation of max rpm, with setting just below it in most cases. As you're cutting you could see that your saw is running at the max power rpm listed as a check up to this.
You might ask one of your friends to confirm that the saw in question is indeed tuned correctly and four strokes when lifted from the cut(taken off of load from the dyno), then it might be possible that if when you try doing the same see if you can feel the difference in the saw motor from running clean to breaking up and four stroking. Might also be if you place your hand on the saw to feel it run to set the idle between running rough lean/rich and follow with the recommended idle speed setting with a tachometer. You could also place a neon spark testing device between the plug and wire to see it running smooth vs rough as well.
On limited coil saws, you can set it to just under the limit of rpm with the tachometer to know where your at and have a starting point. When you get crazy readings, you'll know you went over.
When checking spark plugs try and shut the saw down as quickly as possible after a wot run so a good reading can be attained and not influenced by the idle tune.
I can't honestly say that any of the things I mention will work for you, other than maybe it will spark an idea that you can try to use in an unconventional way that can be conventional for you.
Best of luck with this endeavor and your dyno running.

 

[drf256]

I wonder if someone could/would create a tuning app for this application. The name escapes me, but someone on AS made a cellphone app that could tell the rpm of the saw in a video. Many busted the guy’s balls, but his app was pretty accurate.

Distinguishing between the 2 and 4 stroke sound shouldn’t be that hard to do, i just dont have that know how.

Can you feel any difference in vibration in a saw that another tells you is fat vs. lean?

 

[Stump Shot]

I also happen to wonder what would show up on a vibration tachometer going from running clean to four stroking.

 

[Dieselshawn]

I wonder if someone could/would create a tuning app for this application. The name escapes me, but someone on AS made a cellphone app that could tell the rpm of the saw in a video. Many busted the guy’s balls, but his app was pretty accurate.

Distinguishing between the 2 and 4 stroke sound shouldn’t be that hard to do, i just dont have that know how.

Can you feel any difference in vibration in a saw that another tells you is fat vs. lean?

I’ve not actually tried that. Getting the feel of the saw at different tunes when I have someone set it for me.

 

[schreib69]

Hello fellas, I’m attempting to learn to tune saws after doing modifications and using the dyno.

I am deaf

I’m open to learning here, thank you.

Very interesting post. It appears you created a dynamometer; you called it a dyno but the thread talk here only mentions tach readings. So, I am a bit confused as to if it truly is. If so, I want one!

Also confused because most of the tuning talk is beyond me since I do not understand the intricacy of sound-tuning myself, 4 stroking . . . huh?! ha! I have ears but of no value without training.

If truly a dyno, it seems you could run up to WOT and simply maximize the HP under full load(20" log?). It appears spark plug color / look is involved too. It appears the main reason for doing this tuning is to accommodate a modified muffler for more power; this was left unsaid if so.

Being I am a trained experimenter, I would try this:
-- under existing carb settings, run up to WOT at load, record HP & RPM, carb settings, take image of plug
-- tweak carb in both directions from existing, repeat data /pics
-- use the data / pics to guide further tweaks-- pretty simple.
-- when WOT maximizes HP, stop. Record RPM and HP, take pic of plug, and tune for idle
If idle tuning somehow can affect WOT / HP. . . recheck HP take pic. If not much different, leave it.

Like I said, I don't understand the main process but only trying to assist in experimental guidance. Random efforts are often very frustrating. Regimented, pre-planned experiment may help.

Your work here could be very useful to many people. It would be nice to have a "by the numbers" tuning procedure.

I understand I ignored the fact you live in town and no access to logs, sorry. It seems this is something that you cannot get around if you really want to use the dyno to tune. Get a logger friend to drop one off. . .

 

[Loony661]

I’ve not actually tried that. Getting the feel of the saw at different tunes when I have someone set it for me.

I can only imagine that your sense of feel is greater than those of us who don’t have to rely on it at much? Maybe I’m wrong. But if your other senses are heightened, this could be a way to learn tuning conditions possibly - although I fear it may change from saw model/platform since some are better Anti-Vibed than others..

 

[Stump Shot]

although I fear it may change from saw model/platform since some are better Anti-Vibed than others..

Could be possible to make a remote throttle assembly that could be attached to the saw handle and have the control near the load valve so as to leave a free hand to put on the top cover of the saw to get a better feel. I believe that some chainsaw mill saw rigs have such an apparatus for example.

 

[Dieselshawn]

I wonder if someone could/would create a tuning app for this application. The name escapes me, but someone on AS made a cellphone app that could tell the rpm of the saw in a video. Many busted the guy’s balls, but his app was pretty accurate.

Distinguishing between the 2 and 4 stroke sound shouldn’t be that hard to do, i just dont have that know how.

Can you feel any difference in vibration in a saw that another tells you is fat vs. lean?

I’m gonna check this out. Thank you

 

[Dieselshawn]

I can only imagine that your sense of feel is greater than those of us who don’t have to rely on it at much? Maybe I’m wrong. But if your other senses are heightened, this could be a way to learn tuning conditions possibly - although I fear it may change from saw model/platform since some are better Anti-Vibed than others..

Yes that’s true. But I have to learn to get that feel and I’m just starting.

 

[nixon]

I wonder if someone could/would create a tuning app for this application. The name escapes me, but someone on AS made a cellphone app that could tell the rpm of the saw in a video. Many busted the guy’s balls, but his app was pretty accurate.

Distinguishing between the 2 and 4 stroke sound shouldn’t be that hard to do, i just dont have that know how.

Can you feel any difference in vibration in a saw that another tells you is fat vs. lean?

I believe his first screen name was “ woodheatwarrior “ He changed it to something else ( which I can’t recall ) . I believe he may still post there at times .