Fuel in Magneto Case...

Discussion in 'Mounting Techniques for Bicycle Motors' started by signet, Sep 3, 2017.

  1. signet

    signet New Member

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    Hello all: I am new here, and relatively new to the gas bicycle thing, but have a lot of mechanical experience, including messing around with some old-time 2 cycle lawn mower engines...

    What I'm getting with my 2 stroke 50cc bicycle engine is an excessive amount of fuel leaking into [and out of] my magneto case... This can't be right... I can see that the magneto case is at the lowest point of the engine, and so that part doesn't surprise me... And I know that some gas/oil mixture must get to the bottom of the engine to lubricate it... But to the point where it is soaking the magneto windings, then leaking out onto the ground?!...

    For my money, the magneto magnet shaft should have a seal to prevent this... But I don't think it does... Anyway, I think having fuel in a part of the engine where there is an electrical voltage present is dangerous...

    Perhaps I've already wiped the cylinder walls, and am leaking too much fuel into the bottom of the engine?...

    Any help at all would be appreciated...

    Signet
     
  2. crassius

    crassius Well-Known Member

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    if it isn't dripping down from the carb and leaking thru the cover gasket, then it is coming out of the bottom of the motor - this usually means that the seal behind the rotor is leaking, but may also be from the 4 screws holding the armature being loose
     
  3. signet

    signet New Member

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    Well, it's not coming from the carb... It has to be coming through the magneto shaft... So there is a seal on that shaft?... Right... I really think my first engine is a dud... Ordered another one, and it's here...
     
  4. crassius

    crassius Well-Known Member

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    seal leaking is no big deal, it may just have gotten put in a bit crooked at the factory
     
  5. mbearden

    mbearden Member

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    More than likely the oil seal on the magneto/magnet shaft behind the magnet, if, like said above, it's not leaking down from somewhere else. The fuel is probably coming in from the crankshaft. That would be my guess.
     

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