Tach tuners vs ear tuners

[Old2stroke]

Hope this thread doesn't get as ugly as oil threads, but here goes anyway. This is all about adjusting the high speed jet, and the disadvantage for those of us who do it by ear, is that a large log is needed so that the saw can be operated at full power in the cut for a reasonable time. Sucessive cuts are made as the "H" screw is adjusted to zero in on the sweet spot where the exhaust note at full throttle out of the cut has a rich burbble to it but becomes crisp and clean in the cut. Some muffler designs make this point difficult to find and some engine designs like stratos can also be difficult. The process takes patience and a willingness to experiment but the advantage is that once the skill is acquired, the saw can be set for optimum performance and longevity under all conditions of temperature and altitude.
Tach tuners on the other hand, run the saw at full throttle, no load, and adjust the "H" screw to set the rpm to a value recommended by the manufacturer. Dealers and repair shops love this method as it is quick and easy and the saw doesn't even get dirty. They also don't have a big log in the backyard to do test cuts with and many of their mechanics wouldn't know what to do with it anyway. The down side is the rpm specs that the manufacturers provide are selected mainly to comply with mandated emission standards and have little to do with the longevity of the engine. This method might only be valid for new saws that meet the manufacturers +/- tolerances on engine components and with their recommended oil type and mix, and the setting achieved is only good for a limited range of temperature and altitude. Many saws coming from dealers, repair shops and box stores are just set too lean and this is one of the major causes of engine damage. The method has another issue; do you really think it is good for a saw to be run at full throttle, no load, for the length of time it takes to get a stable tach reading? Would you do that to any other engine?

 

[cus_deluxe]

I dont think theres anything wrong with a bit of time at WOT, its a chainsaw ffs not a ferrari lol. I have a tach, generally use it after doing some grinding to see if there was a change in max rpms. For saws i do for others i tune by ear/in the wood. Nice to have a tach to check idle speed tho.

 

[NSEric]

I tuned my ported chinese saws with a tach attached to them while cutting when I had some big wood to block up, I set them for max rpm/power in the cut. Once I had them set to where they cut the best I checked the max rpm with a tach and use that rpm to set them for temp/weather changes as it is quicker and easier. I had a hard time hearing when they were dialed in as they always four stoke a little bit while cutting, tuning by ear wasn't working that good for me on these saws.
The ported 62 sounds best when set to 15000 and still four strokes out of the cut but lacks tq, it cuts best and holds the best rpm in the cut set at 14000. The 52 sounds overly rich set to 13000 but that's where it cuts best and holds 11000rpm in the cut, if I lean it out so it stops four stroking in the cut it has no tq and slows down.
For a stock saw I'd just set it a hair under max recommended rpm with a tach and call it good. It only takes a second or two to get a reading for max rpm, this doesn't hurt the saw.
A bunch of new saws have limited coils now too, this makes tuning by ear tricky as the limiter sounds like four stroking, tuning these saws with a tach is safer.

 

[aokpops]

Dealer tuned saws are gutless .

 

[Jasonrkba]

This thread was recommended to me and helped me a lot.

https://www.arboristsite.com/community/threads/video-how-to-tune-a-chainsaw.113538/

 

[CR888]

If running an unloaded saw wot for a few seconds make you cringe, one should see how test engineers test new off the production line engines. Those guys show NO mercy, they only know of one throttle position...

 

[James Miller]

I tuned my ported chinese saws with a tach attached to them while cutting when I had some big wood to block up, I set them for max rpm/power in the cut. Once I had them set to where they cut the best I checked the max rpm with a tach and use that rpm to set them for temp/weather changes as it is quicker and easier. I had a hard time hearing when they were dialed in as they always four stoke a little bit while cutting, tuning by ear wasn't working that good for me on these saws.
The ported 62 sounds best when set to 15000 and still four strokes out of the cut but lacks tq, it cuts best and holds the best rpm in the cut set at 14000. The 52 sounds overly rich set to 13000 but that's where it cuts best and holds 11000rpm in the cut, if I lean it out so it stops four stroking in the cut it has no tq and slows down.
For a stock saw I'd just set it a hair under max recommended rpm with a tach and call it good. It only takes a second or two to get a reading for max rpm, this doesn't hurt the saw.
A bunch of new saws have limited coils now too, this makes tuning by ear tricky as the limiter sounds like four stroking, tuning these saws with a tach is safer.

Set up a 7910 with a tach below the 12.8k limiter and your giving up performance. The echo 590s are the opposite way there run better set below the low side of the factory specs.

 

[BB Sig]

So I'm sitting on the couch reading this post. Wife asks what im doing. Reading a post on tuning saws. She said "If we talk about a tuning saw will you put the phone down?" I said sure but i don't know what a tuning saw is!

She then asked why i picked the phone back up. I said i had to post this prior to the tuning saw conversation...