Hole in my Cylinder??

Discussion in '2-Stroke Engines' started by seafood10, Jul 8, 2009.

  1. seafood10

    seafood10 New Member

    Hey, put together my first 66cc kit and was breaking it in, about 2-3 hours on it and I noticed oil/gas leaking where the head and jug meet, but not apparently leaking from the head gasket as I can tell from both looking at it and ensuring the the head is torqued down, but i can look again to double check. It is almost as if there is a small hole in the jug, when it runs it occasionally makes a loud crack sound as if the muffler was not attached making me think that I am listening to the internal cumbustion via this hole? The bike runs ok at full speed but come to think of it, it has lost a little performance. I am still breaking it in with 16:1 so I am guessing that the is the reason for poor idling.
    I have been rebuilding Vespa and lambretta engines for over 20 years so I know my way around 2 strokes but have never seen this before, maybe it's a Chinese thing, I dunno. Any ideas?
    EDIT: apologize, don't know why the pics got all screwy like that.

    Attached Files:

  2. srdavo

    srdavo Active Member

    have you pulled the head & checked the head gasket?

    with the head off.... you can also check for flaws in the castings.

    good luck & keep us posted.
  3. seafood10

    seafood10 New Member

    Nope, have not gone that far. I was worried that I would need a new head gasket if I remove the head and do not know where to begin to look for a head gasket, but i can always make one I guess.
  4. srdavo

    srdavo Active Member

    normally, you can get by with reusing your head gasket.
    But my guess is it's already blown.

    several of our site sponsors have gaskets & parts.
  5. seafood10

    seafood10 New Member

    Yeah but that's the thing, the gasket looked clean and intact from the outside, not just my opinion that of others as well. Just wondering if the cheap casting left a hole. The bike does run and I can scoot along but there is some leaking going on. Maybe I pull head today, we'll see.
  6. srdavo

    srdavo Active Member

    nothing would surprise me.....

    have you contacted the person you bought the kit from?
  7. will_start

    will_start Member

    My engine "jug" had a hole in it from the start.
    I have a pic somewhere here, the motor runs fine tho.
    I patched it with Muffler putty, just in case...
    Last edited: Jul 8, 2009