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Adding Some Sauce To Echo 355t

Discussion in 'Chainsaw' started by SierraMtns, Nov 10, 2019 at 10:31 AM.

  1. SierraMtns

    SierraMtns ArboristSite Operative

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    Ran a couple tanks through the saw and it ran good but I think there is more in this saw. So to the bench we go. Surprised at the compression. Tear down and clean up. My plan is to change the bottom transfers a little, raise the intake a touch, and widen the exhaust. Nothing too crazy, just wake the saw up a little more.


    Next is porting timing numbers. I might need your guys help with figuring out the numbers. I am no pro tuner. Just do this for fun on my own saws.

    IMG_9235.JPG IMG_9262.JPG
     
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  2. SierraMtns

    SierraMtns ArboristSite Operative

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    Started getting numbers.

    *Intake*
    Intake opened at 70.5* and intake duration is 219*.

    *Upper Transfers*
    Starts opening 126.5* ATDC

    *Exhaust*
    Starts opening at 68* ATDC

    What do you guys think? Do these numbers seem right?
     
  3. SierraMtns

    SierraMtns ArboristSite Operative

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  4. huskihl

    huskihl Addicted to ArboristSite

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    I think your intake opening is correct at 70.5. But duration would be 141

    Your transfer opening is right

    Your exhaust opening is probably 112. Guessing you read your wheel at degrees after bdc

    All just a guess lol
     
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  5. SierraMtns

    SierraMtns ArboristSite Operative

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    Cool thanks Kevin for the help. I cant seem to figure out which side of the wheel to read when I get to a port. :confused: BDC or TDC
     
  6. huskihl

    huskihl Addicted to ArboristSite

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    Always tdc. Either before or after will give the same number if your wheel is zeroed
     
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  7. SierraMtns

    SierraMtns ArboristSite Operative

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    IMG_9432.JPG

    Laying out the grind lines last night. I am still trying to figure out how many mm equals a degree. I don't want to take off too much, so I am starting at 1mm and then will re-measure with the degree wheel.
     
  8. huskihl

    huskihl Addicted to ArboristSite

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    I wouldn’t widen the intake much without testing. I know of a few models where you’ll go backwards by doing that
     
  9. Yotaismygame

    Yotaismygame Juiced Saws #GetJuiced

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    Cool thread. I'll be doing my 2511t before the year is over.
     
  10. Yotaismygame

    Yotaismygame Juiced Saws #GetJuiced

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    In duration. 136/107/141 with a blow down of 14.5. Exhaust seems a little low, Intake inst bad.

    I've never ported a saw this small but how does this sound? 144/114/148 BD 15
     
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  11. SierraMtns

    SierraMtns ArboristSite Operative

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    Are these the numbers you got on the 2511t?
     
  12. Yotaismygame

    Yotaismygame Juiced Saws #GetJuiced

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    No that was strictly talking about your saw
     
  13. SierraMtns

    SierraMtns ArboristSite Operative

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    lol....Thats what I thought but the numbers are different then the numbers I posted.
     
  14. Yotaismygame

    Yotaismygame Juiced Saws #GetJuiced

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    the first numbers are the ones you posted but in duration. The second set is my proposed numbers after porting
     
  15. SierraMtns

    SierraMtns ArboristSite Operative

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    How do you figure out those numbers?

    So you think the intake is ok? Raise the exhaust a fuzz?
     
  16. Yotaismygame

    Yotaismygame Juiced Saws #GetJuiced

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    To find tdc or bdc numbers from duration you take the duration divide it in half. Take that number and subtract it from 180. 180 total duration. So 136/2= 68. 180-68= the exhaust height of 112. I like measuring port timing in duration. Just my preference. I’ve never ported a saw without doing some machine work on it so my numbers may or may not be good. I was hoping huskihl would chime in. But yes I think it needs more exhaust. I would lower the intake some and raise the exhaust some.
     
  17. buttercup

    buttercup Major General Fool

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    So what you achieve with raising the ports is basically a higher rpm/hp, at the cost of torque and long-livety I would guess?
    Because I know that much about physics - it always comes with a cost...
     
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  18. huskihl

    huskihl Addicted to ArboristSite

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    You kind of have to feel how the saw runs before making too many decisions about what you want to do. Is it a higher strung saw as it sits or does it tractor along no matter how much wood it’s in? Being only 35c, I’d keep the exhaust down as low as I could. My exhaust height on ported 50cc saws is between 106 and 109. At 35cc, I’d be looking for 110-112. It takes a bigger carburetor to support a higher exhaust and more RPMs, and echoes aren’t noted for having large carburetors
     
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  19. Yotaismygame

    Yotaismygame Juiced Saws #GetJuiced

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    So 108-110 exhaust, lower the intake a bit, polish it up, advance the timing and report back.

    I think the last 50cc saw I did had a 106 exhaust and it was a beast.
     

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