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Retro fit a decomp?

Discussion in 'Chainsaw' started by teacherman, Aug 14, 2018.

  1. teacherman

    teacherman Sawturated

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    Well, I aggravated my bruised sternum last week, which derailed my recovery and return to work, something which definitely gets my attention. What was I doing? Starting an 064. The elasto handle needs replaced, but I'd really like to figure out if this saw (and the 056 mag 2) can be retrofitted with a decomp valve. I have two good specimens of each model, and I really like using them. I know the cylinders don't have a boss milled in for this purpose, and I wonder if it's feasible to actually do this, or if it would weaken the cylinder. I don't mind the 044 not having one, but above 80 cc it seems a good idea.

    Thoughts?
     
  2. blsnelling

    blsnelling Site Contributor

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    It's more than the lack of a decomp. IIRC, the 064 does not have timing retard built into the coil.
     
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  3. Ted Jenkins

    Ted Jenkins Firewood by TJ

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    I think you can use a spark plug tap and be done. I have installed a husky type decomp valve before with out any problems. I am not positive what the threads are like on the auto husky decomp valve. As to if the cylinder would be compromised. Yes the cylinder would not be as strong. I would guess that your saw would last longer than you could. Hopefully you will be cutting for 40 more years, but your saw if taken care of could last 50 more years. I have a 056 that I bought new is still running strong. Thanks
     
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  4. teacherman

    teacherman Sawturated

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    I didn't even know that was a thing. It makes sense, though. Thanks, Brad.
     
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  5. teacherman

    teacherman Sawturated

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    Thanks, Ted. I retired from teaching and started a tree service, but I am a late 1950s model, so 40 years would be a stretch.... I appreciate the optimism, though.

    Not sure why they now put these on 50 cc saws, but ease of starting is definitely a plus, and it's an individual thing, kind of like the power assist accessory for lifting the Shop smith slide pole assembly.
     
  6. teacherman

    teacherman Sawturated

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    One question: Is a husky decomp better made, or is it the size of it that fits better for a retrofit?
     
  7. teacherman

    teacherman Sawturated

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    The 044, 064, and 056 m2 are my favorite big saws, hands down. A fresh 44 might benefit from a decomp as well, I suppose. I was bummed, because I was well on the way to recovering, and this really set me back.
     
  8. blsnelling

    blsnelling Site Contributor

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    Most often guys talk about "timing advance" in a coil. In reality it's timing retard at very low RPMs designed to make the saw easier to start. Once started, they quickly return to normal timing.
     
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  9. Stihl 041S

    Stihl 041S Tree Freak

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    I don’t know Ol Buddy. The Climbing championship in the UK had an 83 year old competitor.
    And get the “D” handle for your says. From the rescue saws.
    Like $5 from Stihl and $11 from aftermarket.
    Take care of yourself.
    Sorry we lost the pictures you posted of your buddy the arborist that passed a few years ago. They were EPIC.....
    Wished I’d saved them.
     
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  10. teacherman

    teacherman Sawturated

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    I have them on disk. I plan to someday restore the thread, which is why I keep the link to it in my sig line.
     
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  11. teacherman

    teacherman Sawturated

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    The same principle applies with a centrifugal advance on a car distributor, right?

    I so like the 064 that I have a part saw coming any day. Paid a bit (lot) more than I'd have liked, but I want to put its intact tank/handle and HD AF setup on a hardly used one I got last year that has the homeowner AF on it and a repaired handle.Maybe I can experiment with the jug from that one and figure out a decomp configuration.

    Th 56 has a slanted cylinder, which might not lend itself as readily to a decomp. Love the old school grunt
     
  12. Stihl 041S

    Stihl 041S Tree Freak

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    Teacherman......if you need a spotface, drill and tap let me know.
    Easy on a mill.
     
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  13. Yukon Stihl

    Yukon Stihl ArboristSite Guru

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    Put a 066/660 cylinder on the 064.Most of them have a decomp.
     
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  14. 67L36Driver

    67L36Driver Tree Freak

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    Handle on my 655BP I got from Lowes several years back is cushioned along the finger area.
    [​IMG]
    Helps a lot!

    And a standard valve from Stihl or Husqvarna can be tailored to one’s desire. Simply drill the bleed port larger. I ended up at 1/16” on the MS880 I rebuilt.
    [​IMG]
    So, even a skinny little geezer can pull start an 880.

    The valves are alike except for the knob color from what I can see.
     
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  15. teacherman

    teacherman Sawturated

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    Is it the same stroke? Also, is the case the same width? I was under the impression the 0_4 series has a narrower body than the 0_6 line. That might be easier if it bolts right up.
     
  16. Stihl 041S

    Stihl 041S Tree Freak

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    Or a 650 cylinder....they had decomp
     
  17. Stihl 041S

    Stihl 041S Tree Freak

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    Yup. It will work
     
  18. teacherman

    teacherman Sawturated

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    Thanks for the offer! I wonder if a Shop Smith horizontal drill press with a vise would serve for this purpose. Seems it might.

    The parts 064 came today. It fires but doesn't run. However, it has the HD AF setup, and a nice tank, which will be transferred over to one with a repaired tank and the old homeowner type AF. The whole housing and possibly the tank is different, so glad I'm switching out the tank. That one I think I got for under four bills, and the seller said it was only used as a firewood saw, so I should have a sweet one there. Definitely will put elasto on it, if not try to mill in a decomp. I need to look at the 660 for placement of it, because the top center is awfully =close to the spark plug inlet.
     
  19. Jacob J.

    Jacob J. Tree Freak

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    066, 660, and 650 cylinders are not a bolt-up situation on an 064 case. The mounting holes need slotted inward diagonally and a tiny amount of shaving of the outside of the cylinder base is necessary.

    You'd also need to drill a hole in the 064 top cover for the valve to stick out of (easy enough).
     
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  20. Stihl 041S

    Stihl 041S Tree Freak

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    Jacob is right.
    As a machinist a little work with a file falls under “it will work”
     
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