Skyhawk Stage III Crank Case Binding

Discussion in '4-Stroke Engines' started by Rasaraja, Dec 8, 2010.

  1. Rasaraja

    Rasaraja New Member

    Hello All,

    I'm building a 49cc 4 stroke with a Skyhawk Stage III Crankcase. When I attach the crankcase, the enclosure hits the left gear and I cannot pull start. What am I doing wrong? All appears to be seated correctly.

    Thanks in advance for any help.


  2. MotoMagz

    MotoMagz Member

    The gear on the left in the picture?

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    Last edited: Dec 8, 2010
  3. MotoMagz

    MotoMagz Member

    This is the clutch in the photo is the one you should have.

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  4. Rasaraja

    Rasaraja New Member

    Yes. That's the gear and clutch. Thanks for the pictures. The casing on the left side comes right up against the left clutch covering. I'll compare the assembly with your pictures tomorrow. From your pictures it appears that the left center post comes out a bit - with mine, the center hole of the gear is flush.

    I'll try to post a picture.

    Thank you again.
  5. BiMoPed

    BiMoPed Banned
    [para 4] Note: On some China engines the crankcase screw head on the right side of the flange opening must be modified so it does not hit the gear box at the #16 bearing pocket boss area.

    To modify, delete the lock washer and file off 1mm from the top of the screw head to gain 2mm total clearance.

    After installing the gear box check for air gap clearance with a flash light or paper insert.
    This problem does not seem to occur when using Honda GXH50 engines but always check for clearance after gear box installation.
    ( Do not grind on the gear box bearing boss: ) Check engine shaft for correct ID

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  6. Rasaraja

    Rasaraja New Member


    I got it figures out (couldn't get a good picture), but I had the left gear's post in backward - it caused that gear to be out too far. Hopefully, it'll be finished tomorrow. ;)

    I do thank you for your help.