Running 2 stroke engine with slightly worn crank bearing?

Discussion in '2 smokers' started by john479, Oct 12, 2011.

  1. john479

    john479 Been here awhile

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    I got a 1981 TS250ER a couple of weeks ago. I took it for a run and somehow air got into the oil feed to the bottom end and so now the flywheel side has a very small amount of play in it. From a certain RPM up there is a vibration noise. Performance is still fine and there is an oil feed to it now working normally.
    I have an enduro coming up and have no time for a rebuild before it, as it needs a rebuild I will by no means be racing, just tootling along and taking it easy. The race is only for 2 hours split into 2 1 hour sessions. Would it be safe to ride it like this? I don't really want to lose my entry money but certainly don't want a major problem caused from running. Thanks very much
    #1
  2. dlrides

    dlrides 1:1.618

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    No
    #2
  3. Tosh Togo

    Tosh Togo Long timer

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    What he said...

    If you really have to ride the event, take a good tow rope...you'll probably need it to finish the first hour. :1drink
    #3
  4. OldPete

    OldPete Be aware

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    Loose crank means the seals will leak, sucking in air & grit.
    When strokers suck air at the crankcase... they lean out, leading to seizure.

    GADS! they run fast as they lean out... N-Joy!
    #4
  5. darmst6829

    darmst6829 Been here awhile

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    I don't think a small amount of play is a big deal. I have run Spanish two strokes so loose the flywheel rubbed the cases! Do the race then rebuild it. What the worst that could happen?

    Dave
    #5
  6. Switchblade315

    Switchblade315 Long timer

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    boom:huh
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  7. lemieuxmc

    lemieuxmc Banned

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    You could probably thrash that thing for another 20 years without a noticeable change.
    #7
  8. mikeyam187

    mikeyam187 n00b

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    It could throw the rod thru the case and you would have a much bigger bill to fix it then!
    #8
  9. stainlesscycle

    stainlesscycle Long timer

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    depending on how noisy it is i'd probably run it. which bearing is it that's bad? if it's not the rod bearing, it'll probaly run for a while.... either way you're gonna split it to fix it. now or later...
    #9
  10. john479

    john479 Been here awhile

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    Thanks everyone.

    I didn't run the event although it could have done it easily as a rode it a bit after and nothing went wrong. After splitting the case I found that the crank bearing journel is worn on the flywheel side. Not caused by me as it's been vibrating since I first started it after I got the bike.

    As a temporary fix I've used some loctite retaining compound to take up the gap between the bearing and the journel and so far it seems to be working. Am on the look out for a replacement crankshaft though for it to be as good as new.

    Thanks again,

    John
    #10