Home Forums Tech Talk MY09 Leopard hot bottom.

This topic contains 6 replies, has 5 voices, and was last updated by  Daniel Wendel 5 months ago.

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  • #67225

    Daniel Wendel
    Participant

    I have a MY09 leopard I am unsure of how many hours are on it.
    The issue I am having is that the bottom end throws off a lot of heat when the engine is above 15,200rpm. I can feel the heat through the right side of my seat. So the magneto side of the engine. Coming of track the crank nut is quite hot.
    Normal or time for a bottom end rebuild?

    #67226

    Matt Martin
    Participant

    high rpm = high speed = modified airflow which hits the seat when it normally doesn’t?  if it’s building that much heat, that you’re able to feel it only when the RPMs are high (i’m assuming this isn’t a steady-state), then the motor would have already gone kaboom, or started making awful sounds.

    #67232

    William Martin
    Participant

    Can you wiggle the crank nut up/down enough to notice? If so, check your main bearings before you carve a trough in the cases with your connecting rod…or maybe push it through the block! This doesn’t sound like an “airflow” heating issue to me…

    Good Luck,

    Bill Martin

    #67234

    Daniel Wendel
    Participant

    I can wobble the crank up/down if I rock it where the clutch cover bearing would be. I am just going to replace the bottom end bearings since I have no idea how may hours are on them.

    #67267

    Craig Drabik
    Participant

    I’ve had freshly built Leopards that throw off enough heat at high revs late in a session to feel it through the seat, so I wouldn’t say that lone is an indication that there’s a problem.

    If you can rock the crank then you should do a bottom end.

    #67271

    Walt Gifford
    Participant

    use castor oil.

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

    #68077

    Daniel Wendel
    Participant

    Just a follow up,
    I rebuilt the bottom end. When I separated the case I found the magneto side crank seal to have failed. Which I guess was blowing pulses of air out at high rpm.
    Raced it last week and no extra heat was felt.

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