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Tuning a 346XP and 372XP with a dual port muffler

Discussion in 'Chainsaw' started by Jtheo, Feb 25, 2011.

  1. Jtheo

    Jtheo Addicted to ArboristSite

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    I have tuned my 346XP with a dual port muffler at 13,800,

    and The 372XP with a dual port muffler and ported top end at 13600.

    A lot of you guys know more than me about this.

    How does this RPM range sound to some of you?

    These are work saws and I want to tune them right, but I am not trying to squeeze every last drop of power out of them.

    So what do you think?

    Thanks for your help.
     
  2. nmurph

    nmurph ArboristSite.com Sponsor

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    my MM 346 is tuned to 14.1K. the second port is pretty much the size of the 288 deflector. i think you are safe.
     
  3. sunfish

    sunfish Fish Head

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    My OE 346 is at 14,200.
     
  4. blsnelling

    blsnelling Site Sponsor

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    Both sound significantly low, especially the 372. I would expect a ported 372 to turn 14,500-15,000.
     
  5. Roanoker494

    Roanoker494 Addicted to ArboristSite

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    I can tell you that the stock limited coil on my 372 is stamped 13600. If my stock saw could handle that I would think a modified saw could handle a little more.
     
  6. 7hpjim

    7hpjim Addicted to ArboristSite

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    rpm's sound good for a spec sheet, does it clean up in the cut?,Brad and some others have posted EXCELLENT tuning vids, if you spec sheet tune w/tach you could have a saw that is over rich and peforms poorly compared to a properly tuned saw!, with a modded muffler it could be lean which is very bad!!!:msp_scared:use the search function:msp_biggrin:
     
  7. komatsuvarna

    komatsuvarna Arboristsite MVP

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    Humm, My 372 was stamped 13,300. Its an 09,, I guess they detuned them more than the earlier ones.
     
  8. blsnelling

    blsnelling Site Sponsor

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    Has the limited coil on the 372 been replaced? I will not port them unless the owner purchases an unlimited coil. It just makes tuning so much easier and safer.
     
  9. 7hpjim

    7hpjim Addicted to ArboristSite

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    yup I got an 09 too, evil black coil is in its near future!!
     
  10. 7hpjim

    7hpjim Addicted to ArboristSite

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    mod muffler, replace coil, trim tabs and viola first modded saw is complete w/noticeable gains and you don't have to get any chips on ya!!!
     
  11. komatsuvarna

    komatsuvarna Arboristsite MVP

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    That was the first thing I changed on mine. Im still learning,and the unlimited coil made it easier on me.

    OP, My 372 is stock(for now) with a MM. I tune by ear,, and check with a tach just to be sure of what im doing. Mine is turning 13,900/14,000. It may be just a hair rich, but it feels about right to me. Im leaving it alone till after I do some work to the cylinder.
     
  12. Jtheo

    Jtheo Addicted to ArboristSite

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    Both have unlimited coils.

    I know there are some good vids on tuning and yours is one of them, but I have a hearing loss and can not pick up when the saw is 4 stroking, so I am at a dis advantage there.

    One thing I can do is keep a check on the spark plug to see if it is showing too rich or too lean.

    I guess part of my concern is that I don't want to push the rpms too high and blow up the saw. I did the muffler mods myself and this is a first time for me.
     
  13. blsnelling

    blsnelling Site Sponsor

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    Doing initial tuning by plug reading is extremely risky. By the time the plug colors, you have had way more than enough time to burn it up. You've got to find someone with a good ear to tune that saw for you. You can then replicate that tune with a tach. I would ask whoever built it what they tuned it to.
     
  14. oscar4883

    oscar4883 Addicted to ArboristSite

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    Have you tried tuning them in the cut? When I try to tune out of the wood it all sounds the same to me. However, I can tell the difference sound wise, when I tune and check the tune in the cut. Depending on how bad your hearing loss is this may work. Mine is not the greatest either.
     
  15. Jtheo

    Jtheo Addicted to ArboristSite

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    Okay, got you on that, I will call in some help. Actually take it to someone who can tune it by ear. Thanks for the help, and thanks to everyone here who is making suggestions.

    Both these saws are just about new and I really don't want to screw them up.
     
  16. Jtheo

    Jtheo Addicted to ArboristSite

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    I can do that, I will put them in some wood tomorrow and see if I can tell a difference in the sound.
     
  17. walkerized don

    walkerized don ArboristSite Lurker

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    Hi. I am Don Walker. You have probably heard of Walkerized saws which I have built. The 346 model can be tached out at around 14,200. Keep a sharp chain, good fresh mix and it will last you forever. The 372 with the black ignition is a non-rev limiter ignition and you can tach it at the same as the 346. My customers here in Canada run 33" bars on 372 and they last for a couple seasons of steady work. Any questions email me at timber-1966@hotmail.com.

    Don
     
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  18. Jtheo

    Jtheo Addicted to ArboristSite

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    Thanks Don, Yeah I have heard of Walkerized saws.

    On the 372, right now I have it tached at 13800. The 372 is ported.

    The 346 was up to 14000, and I backed it down to 13500. The 372 is ported, but the 346 has only a dual port muffler and it was screaming at 14. Besides the 346 is really not broke in yet.

    No blue coils on either saw.

    Thanks again for the info.
     

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