Oil coming out of my exhaust

Discussion in 'Tech Area' started by mk2davis, May 5, 2021.

  1. mk2davis

    mk2davis Member

    Joined:
    Nov 15, 2016
    Messages:
    53
    Likes Received:
    9
    Hello boys and girls! I have a CT that runs like a honey, as long as you can outrun the smokescreen.

    The valves seem to be seating well, rings look good (still springy), cylinder looks undamaged.

    What I did notice when I took off the head and jug is that there seems to be a lot of oil coming from the upper right stud. I know that oil divider feeds the intake valve, so I should see a little oil.

    I'm wondering if the gasket is bad or a blockage preventing the oil from draining... then finding its way to the cylinder?

    My harbor freight leak down tester shows in the green, with some leaking out the intake and rings, but definitely serviceable. I don't know what else could be.

    I'm going to try and google it, but if someone could share the route the oil takes in the head, that would be useful. I noticed the aluminum cam chain cover was hot when running. I do have oil flow, I checked that.

    For what it's worth, things got worse after an oil change.
     
  2.  
  3. mk2davis

    mk2davis Member

    Joined:
    Nov 15, 2016
    Messages:
    53
    Likes Received:
    9
    I've addressed this issue by replacing the top end, and as far as the bike is concerned no more oil out the exhaust.

    Please let me know what to look at in the head or piston and jug. One thing I saw was the outside diameter of the middle ring was smaller than the other rings. It also had a considerable gap with the ring tight around the piston of maybe 1/8 to 3/16 of an inch. Piston is .050 over, I'm guessing they broke the replacement middle ring. I'd assume this would lead to a lack of compression more than oil leak, but maybe someone can school me up.
     
    #2 mk2davis, May 5, 2021
    Last edited: May 5, 2021
  4. lukelaw1

    lukelaw1 Active Member

    Joined:
    Jan 28, 2013
    Messages:
    738
    Likes Received:
    115
    the exhaust valve has a seal around the valve stem.#8 ct70k0-cam-and-valves-1.gif
     
    Gary likes this.
  5. Old Guy Too Many Bikes

    Joined:
    Nov 11, 2020
    Messages:
    102
    Likes Received:
    21
    One thing to also check is to make sure the engine case vent tube is not blocked or kinked. If it is, the excess pressure will come out through the seals and rings, causing leaks and smoking. Don't ask me how I know...
     

Share This Page