Cleaning my bottom
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Thread: Cleaning my bottom

  1. #1
    Member bikerdaily's Avatar
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    Cleaning my bottom

    So I'm cleaning up my sohc 250 engine and there is a blue rubber stuff where the top and bottom gearbox cases join. Tell me I'm right in assuming a) Honda didn't apply this type of gasket when they built their engines and b) therefore my 15k miles engine has been apart?

    Oculi plus vident quam oculus
    1981 Honda cm250tb rebuilding
    2013 BMW R1200R daily ride
    1980 Yam XT250
    www.hondacm250tb-biker.co.uk

  2. #2
    Sensei 66Sprint's Avatar
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    The correct sealant is NOT blue....So YES, it's been apart and now NEEDS to come apart again.....
    chaindrivecharlie likes this.
    "I have a mind like a steel trap.....Old and rusty, of antiquated design, and hard to get stuff back out of...."
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  3. #3
    Senior Member oupa's Avatar
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    Well now, THAT's a relief! With a title like "cleaning my bottom" I was never happier to find a thread about "form a gasket!"

    ...come to think of it, this is the first time I've ever been happy to find a thread about form a gasket.
    J-T, 12ozPBR and Bill H like this.
    "They're not like cars with a body that rusts out in a few years. Keep them tuned and overhauled and they'll last as long as you do. Probably longer." - Robert Pirsig

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  5. #4
    Member bikerdaily's Avatar
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    Sensei
    So why do you say it NEEDS to come apart again? Is this because it has the wrong material for the gasket?

    Oculi plus vident quam oculus
    1981 Honda cm250tb rebuilding
    2013 BMW R1200R daily ride
    1980 Yam XT250
    www.hondacm250tb-biker.co.uk

  6. #5
    Sensei 66Sprint's Avatar
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    Well, yes.... Because that sealing material is likely either a RTV or a silicone sealant, and both types tend to extrude "globs" of semi-hardened material that break off and ultimately end up clogging oil passages within the engine....

    There IS a blue sealant called Hylomar which could be OK, IF it was properly applied, but that is at best a 33% chance of success vs a 66% chance of catastrophic engine failure...... I don't like those odds against ......

    Disassemble, scrape off that mess, clean out the sump and inspect and clear all internal oiling passages...Particularly the oil pickup screen, oil pump, and filter....Inspect ALL bearings, journals, and bearing surfaces (plain bearings).. Then reassemble with the proper sealant (Hondabond Silver or Threebond) on the case halves, and new gaskets throughout ......

    YES, I am discussing a total engine tear-down to bare cases both top and bottom ends.....You MAY not have to go quite THAT far, but won't know until you open her up and inspect.....
    Last edited by 66Sprint; 05-16-2019 at 02:19 AM.
    chaindrivecharlie likes this.
    "I have a mind like a steel trap.....Old and rusty, of antiquated design, and hard to get stuff back out of...."
    Contact info: E-mail; [email protected] Phone; 540-525-5199

  7. #6
    Member bikerdaily's Avatar
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    Aaaaarrrrgggghhhh.

    Oculi plus vident quam oculus
    1981 Honda cm250tb rebuilding
    2013 BMW R1200R daily ride
    1980 Yam XT250
    www.hondacm250tb-biker.co.uk

  8. #7
    Senior Member ancientdad's Avatar
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    Quote Originally Posted by bikerdaily View Post
    Aaaaarrrrgggghhhh.
    lolz...
    Tom

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  9. #8
    Senior Member chaindrivecharlie's Avatar
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    Quote Originally Posted by bikerdaily View Post
    Aaaaarrrrgggghhhh.
    Good pirate responce matey!😁

    Better to be sure, than pushing a motorcycle down the side of a highway.
    Charlie

    1972 CL 175 K6
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    1981 CM 400 C

    Joshua 24:15

  10. #9
    Super Moderator longdistancerider's Avatar
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    If there's blobs of sealnt on the outside I'll guarantee there's some on the inside. The sealant is applied as a VERY thin smear to the surfaces since it's only sealing the slight machining imperfections.
    chaindrivecharlie likes this.
    Jim O'Brien
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