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Stihl BR420 piston in Stihl 034 saw

Discussion in 'Chainsaw' started by John Lyngdal, Feb 14, 2020.

  1. John Lyngdal

    John Lyngdal ArboristSite Guru

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    Both have the same bore and stroke and just looking for a replacement piston for the saw I have torn apart. The pistons look similar and I could machine the piston if needed.
     
  2. Mad Professor

    Mad Professor Addicted to ArboristSite

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    Why not use a 034 piston, OEM or Meteor?
     
  3. Conquistador3

    Conquistador3 Le Comte de Frou Frou

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    Kinda of sensible advice coming from a Mad Professor. ;)
     
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  4. Jkstihl

    Jkstihl Chainsaws make me fap.

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    Yeah not sure why you wouldnt just go with the 034 piston..
     
  5. SEAM

    SEAM Addicted to ArboristSite

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    Probably would be too easy... Might actually be the exact same piston, who knows?
     
  6. drf255

    drf255 BAD CAD

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    Same bore and stroke does not mean the piston is the same. Pin size and compression height may differ. Design may differ as well.

    Use a stock piston. If NLA, you may need to move to a 48mm top end.
     
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  7. Mad Professor

    Mad Professor Addicted to ArboristSite

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    OEM and Meteor both list 46mm 034 pistons. Stihl piston is pricey, ~$80.

    I don't have a BR420 IPL to check part # for piston. If it is same as 034 it will be 1125 030 2002. I doubt it is, cylinders are much different.
     
  8. Mastermind Worksaws

    Mastermind Worksaws The Enabler

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    Good morning Al.
     
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  9. cuinrearview

    cuinrearview Red saw lover

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    Seems like the 46mm stuff is usually pretty cheap because most go 48mm when replacing parts. I understand though if you have the part sitting in front of you. Let us know if you end up giving it a go, and take lots of pictures.
     
  10. John Lyngdal

    John Lyngdal ArboristSite Guru

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    The swap was inspired by the modified 028 piston I have on my 024.
    Spotted an inexpensive 46mm BR420 Chinesium piston for sale and so I posed the question.
    The OEM piston has some minor scoring, but really only needs to be cleaned up and have a new set of rings installed to be put back in service.
     
  11. Mad Professor

    Mad Professor Addicted to ArboristSite

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    Glad to see the Monkey back!
     
  12. Mad Professor

    Mad Professor Addicted to ArboristSite

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    Buy a Meteor for ~$35 USA and be done with it. Or pony up for a OEM.

    How much time would you have into it make it fit? Would it be worth ~$15? Or ~$65 OEM?

    Then if it blew up in ~5 minutes..........and trashed the clyinder........

    P.S. I still have two Stihl NOS/OEM 46mm 034 cylinders, no pistons, on trading post......
     
  13. DND 9000

    DND 9000 ArboristSite Guru

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    The pistons are not the same. The BR 420 piston is 4203 030 2001.
     
  14. Mastermind Worksaws

    Mastermind Worksaws The Enabler

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    Just passing through.
     

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