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Stihl BR420C Magnum cylinder

Discussion in 'Mechanic and Repair' started by AuthenicStihlEquipment, Apr 15, 2010.

  1. AuthenicStihlEquipment

    AuthenicStihlEquipment LawnSite Member
    Messages: 27

    I just purchased a used Stihl BR420C magnum. it was a basket case machine that was all torn down but it looked almost new. it looked like it had a blown cylinder gasket. The only thing I am not sure about is at the very bottom of the cylinder sleeve on the manifold side and not quite in the center it looks like a small chip of the nickle plate finish some how came off. the surface is still smooth where the finish is gone. the nickle plate that is missing is about the size of a bb for a gun maybe alittle bigger. is there anything that can be done to fix the finish that is missing. would it still be safe to run it the way it is or would the rings get caught on it.
  2. AuthenicStihlEquipment

    AuthenicStihlEquipment LawnSite Member
    Messages: 27

    no one out there knows anything about cylinders. This is the first time in 25 yrs of working on small engines that I have ever seen a cylinder that was missing some of the nickel plate finish. The seller that sold this unit thought the engine was ok and only needed a set of rings. thought I would get another opinion before deciding if I should try to run it like it is or replace it. Any advise would be helpful and appreciated. Thank you
  3. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,279

    Well I see it all the time when they run raw gas or even when high corn gas is used in Echo. I hand sand off the rough edges and put in new rings in Echo and get them going. I mainly use them as backup units haven't had any fail out of ten I have done in the last 3 years.
  4. sharkey

    sharkey LawnSite Member
    from Pa
    Messages: 50

    If the chip is below where the rings normally ride, it shouldnt matter.
  5. Alan0354

    Alan0354 LawnSite Platinum Member
    Messages: 4,450

    I agree. Sounds like it is below the rings ever touching. Could be factory defect from day one. Beside it is spilted milk already, fix the existing problem and time will tell.

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