bogging 66 gt5

Discussion in '2-Stroke Engines' started by beentryin, May 19, 2010.

  1. beentryin

    beentryin Member

    i have a skyhawk gt5 its got around 200 miles on it,and it has muffler hogged out gasket macheted both sides and ported then int,ext, and got the clip on the third notch,and it boggs pretty bad on low and bogs less the fast i go or the motor revs? any ideas what it might be?
     

  2. GearNut

    GearNut Active Member

    3rd notch from top of needle or bottom?
    What color is the spark plug? Black and rich, or white and lean?
    Note: do NOT remove the plug to look at it while the engine is hot because you risk removing the threads out of the cylinder head.
     
  3. beentryin

    beentryin Member

    its on the second notch from the bottom any higher it bogs when it gets hot,and my plug is a greyish color after riding about 10 miles with the clip on the second notch from the bottom
     
    Last edited: May 19, 2010
  4. GearNut

    GearNut Active Member

    Grey is generally not good in a 2-stroke. It indicates a lean condition which can do damage.
    You want it to be a toast or leather brown to a chocolate brown.
    There is a balance concerning the jetting which you sometimes have to think "out of the box" to remedy.
    I would want to set the clip in the bottom most groove to enrichen the mixture during low and mid RPM operation. You may have to drill out or solder first and then drill the jet to correct high RPM jetting.
    I am guessing that you live near sea level in altitude, if so then the jet may be manufactured wrong from the factory as typically soldering and drilling is only needed in high altitude areas, and you seem to be running lean (hole in jet is too small).
    Another thing you may be fighting is the cylinder port timing. How much modifying did you do to the ports as far as raising or lowering the edges?
     
  5. beentryin

    beentryin Member

    bogging

    i didnt really take much off the ports but i did clear the piston to match the intake port,and i live in ohio so im not far above sea level,it runs real good cold but start to lose power after it gets hot
     
  6. GearNut

    GearNut Active Member

    Good cold then bad when hot, eh?
    That sounds like a thermally related air leak.
    All things expand when they get hot, shrink when cold (water is an exception, but I am not going there).
    I would do a leak test when the engine is cold and then another one when hot.
    It could be leaking from any gasket or even the crankshaft seals.
    Also, these engines do need some back pressure in the exhaust. Do you still have the end cap attached to your gutted muffler?
     
  7. beentryin

    beentryin Member

    bogging

    yes runs great when cold just loses power when hot, and i also have a whistling noise when i first start it ,sounds like its coming from the clutch area.the muffler wasnt gutted i just hogged out were it bolts on i could barely get my finger in the hole. the muffler is still stock as in the guts
     
  8. GearNut

    GearNut Active Member

    A whistling noise is usually a blown head gasket. A small pinhole in the sealing area is making a chirping noise when air gets blown out of it during each power stroke.
    A leaky base gasket can chirp too, but that is usually at higher engine speeds and the general engine noises mask the fact that it is even there.
     
Loading...