Black Pistons??

Discussion in 'Engine, Fuel and Exhaust' started by DynaBob09, Jan 20, 2011.

  1. DynaBob09

    DynaBob09 Active Member

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    I just completed a 103 Big bore kit on my 2009 Fat Bob. It only had 1000 miles on it. I asked to keep all old parts and the pistons where almost completely covered in black crud. It looks like tar. I only use Premium name brand gas from reliable staions. Is this normal? Whas it the factory tune?
     
  2. Jack Klarich

    Jack Klarich Expert Member

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    Maybe an oil ring problem, was it using alot of oil? Or, maybe bad valve guides and seals leaking oil?
     
  3. Hoople

    Hoople Account Removed

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    Like Jack said, sounds like oil. Both pistons were equal? With only a thousand miles on the bike.
    Pictures would help. Just curious, what brand of oil were you running.
     
  4. DynaBob09

    DynaBob09 Active Member

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    Oil was full when I took the bike in. I had checked it. However, it was the original oil that came with the bike. I had them do the first 1000 service at the same time.
     
  5. Jack Klarich

    Jack Klarich Expert Member

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    HMMMM, still sounds like an oil control problem, did you get any more info? These new pistons have a coating on them is it possible the engine was not yet broke in and the coating on the pistons is what you saw?
     
    Last edited: Jan 20, 2011
  6. DynaBob09

    DynaBob09 Active Member

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    I just looked at the old pistons for the first time yeaterday. Job was done xmas week. Both pistons had the crud on it. I will call the dealer tomorrow and see what they say (probally "dont worry bout it"). I am wondering how my heads looked?? Hopefully, if there was a oil problem, it was related to the rings which are changed now becasue of the 103 kit. I will try to post pictures tonight.

    Both pistons.
    I'll try to post pics tonight.
    Original oil form factory. Now it has Syn3.
     
    Last edited by a moderator: Jan 20, 2011
  7. HarryB737

    HarryB737 Junior Member

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    1000 miles... I hate to be cinical, but I wonder if you got your pistons back?
     
  8. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    Sad if true but a great point!

    Bodeen
     
  9. BUBBIE

    BUBBIE Well-Known Member

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    Now I'll stur the Soup Pot.......

    :bigsmiley18: If your bike had a 1000 miles on it and ran good ...... The pistons you got back were PROBABLY not yours......

    1000 miles would be hard to have Heavy Black deposits like you state ON a NEW bike in that amout of time.. You would of noiticed a problem in Runability...

    SOME ONE probably wanted the old GOOD pistons or just a Mix up.

    It can happen..BOTH WAYS... Waiting for the picts.

    signed....BUBBIE

    OH-ooooo maybe the pistons are Teflon linned.
     
  10. Brutal FXDX

    Brutal FXDX Active Member

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    Here's a pic of a piston out of a 2010 flhr with only 5k miles. Swapped out for big bore last week. Seems to me that every engine i take apart has a decent amount of carbon/oil build up on them, High mileage or not.



    [​IMG]
     
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