Crank seals

Discussion in 'Engine' started by Tcustom, May 12, 2019.

  1. Tcustom

    Tcustom Member

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    im about to replace the crank seals on this thing. Is there any surprises that I need to know about when I take the fly wheel off or the gears off on the clutch side. I had someone just recently rebuild this thing and I have had more issues with it then I should have. If you want something done right just do it yourself. I do have the flywheel tool also. But is there any timing issues or anything along those lines I need to know about? I did a oil change and with one trip down the road now I can barley see the oil on the sight glass, yes I only put 650ml in it. The thing only has low end power and falls on its face right when it should be going into the powerband. Has a high idle, It smokes like a freight train and it has a 290 jet in it now with stock pilot jet 32.5. I can’t get it running good enough to even perform a plug chop test.
     
    Last edited: May 12, 2019
  2. Tcustom

    Tcustom Member

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    im about to replace the crank seals on this thing. Is there any surprises that I need to know about when I take the fly wheel off or the gears off on the clutch side. I had someone just recently rebuild this thing and I have had more issues with it then I should have. If you want something done right just do it yourself. I do have the flywheel tool also. But is there any timing issues or anything along those lines I need to know about? I’m going to perform a leave down tomorrow also. But it’s smoking like a freight train it’s rich as all get out but also has a high idle. I drove it down the street to do a plug chop test it had a fresh oil change and no oil leak but can barely see the oil in the sight glass. With one ride. Has all kinds of low end torque but falls on its face right when it should be going into power band. It’s had jets in it from 310down to 230 with no power difference.
     
  3. Larry's Shee

    Larry's Shee Active Member

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    A manual is your best friend. Biggest thing is timing the balancer. Make sure right seal is facing correct direction, markings face you.
    Oil loss is from sucking through bad seal. Don't worry about plug chop until seal is fixed. Excess oil causes power loss.
    List all your mods, someone will suggest jetting range.
     
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  4. Tcustom

    Tcustom Member

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    How do I know the balancer is timed right. Is there any marks. I can’t think of the guys screen name but he told me with my Mods start with 310 and work my way down. Fresh rebuild 67.92mm fmf gold series pip and silencer stock carb open air box
     
  5. Larry's Shee

    Larry's Shee Active Member

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    Last edited: May 15, 2019
  6. Tcustom

    Tcustom Member

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    Not at all man thanks for the info I will get one. I been a mechanic for 10 years but new to working on the 2 strokes
     
  7. Larry's Shee

    Larry's Shee Active Member

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    Every time I see these words I laugh. It's like because it only has a crank, rod, and piston it must run on pixie dust :D
    If I had a dollar for every time I've seen that, I'd be rich :p

    The only thing very different is in tuning. They do not tolerate poor gas, cheap/wrong oil, and most importantly running lean.
    As they go from rich to "perfect"" jetting power increases a lot and heat a little. When you go from perfect to lean power drops of very little, barely noticeable BUT heat goes to the moon quickly.
     
  8. Larry's Shee

    Larry's Shee Active Member

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    Be sure to do a leak down test to ensure problem wasn't leaking cases.
     
  9. Tcustom

    Tcustom Member

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    I was going to do one before tear down but gaveling trouble finding all the things I need to make one so I figure I’d go ahead and just replace the crank seals. It sucked all 650 ml of oil out of the case with Manet a half mile ride. I do know lean is mean it’s cost me before in my drag car. I thought I give the big car a break because it’s so finicky but this dang thing is just as bad lol. $500 toy don’t hit $1000 quick
     

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