Top end issues.

Discussion in '2-Stroke Engines' started by FrenchFRI3S, Apr 15, 2015.

  1. FrenchFRI3S

    FrenchFRI3S New Member

    Okay to start this off by saying I cracked the head(not my head), I replaced the head(still not me head) and inspected the other surrounding parts and all seems to be fine(except me head). Then my master link decided to take a run for it before even having the bike warmed up.(literally didn't make it half a mile) But, I'm really curious to know one thing.

    Before the head cracked(my real head is fine guys) I had was riding it a couple of miles no real long hard journey or anything and came home and parked it. Now i had not shut off the petcock when it was parked. When I came back to the bike the head was cracked. I removed the spark plug to find it rather wet. I left the spark plug off and gave the motor a good bump, Alot of gas mixture came spraying out and as i figured it would push the excess out.

    The real question is this, has my head being cracked have anything to do with that motor filling up with fuel while still hot? I presume this is how it cracked due to the fact that i had no loss of power or drop in rpms during the ride before parking the bike. All informative information will be taken considerably helpful as to this being my first motor. My current odo reading is 897 miles.
     

  2. jaguar

    jaguar Well-Known Member

    it filled the carnkcase with gas, then when turning over the engine it came up thru the transfers to spew out the plug hole.

    the fuel overflow had nothing to do with the cracking of the head.

    too lean a mixture (incorrect jetting or an air leak) or head gasket leaking can cause the head to get too hot and crack.
     
  3. FrenchFRI3S

    FrenchFRI3S New Member

    Also when i came back after parking it the carburator was the first thing that caught my eye because it looked half frozen. I had not one issue before i parked it and it wasn't no longer than 15-25 minutes ride time. What causes a head to crack when a motor is not in use if the fuel/gas mixture didn't push up to the top of the cylinder pushing heat towards the top of the motor. FYI there was fuel all the way up to the plug hole on the inside and a good bit of gas missing from the tank. I figured it was like putting cold water in a hot motor.
     
  4. jaguar

    jaguar Well-Known Member

    does the spark plug color indicate it was running lean?
    for sure the head/cylinder junction was leaking. they all do. you have to plane them flat using sandpaper on glass
     
  5. Slogger

    Slogger Member

    Since your crankcase filled with gas, there's not much doubt you have a dirty float needle and seat in the carb.
    A little grit gets in there and the needle can't stop the gravity fed gas from flooding into the engine.
     
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