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replacing crank seals rm 250!

Discussion in '2-Stroke Discussion' started by 1998RM250, Apr 1, 2009.

  1. 1998RM250

    1998RM250 Rookie DRN Member

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    Hey guys I rebuilt my top end, and after putting it togather it just rev's like crazy and is sucking oil from the trans. My question is when the cases are split, are these all the seals I need?
    I'm looking at this kit: http://cgi.ebay.com/ebaymotors/SUZU...hash=item380073694346&_trksid=p4506.m20.l1116



    Is there a seal between the cases I need to get as well, or does that seal kit cover everything I need? Thanks for the help!
  2. sick 96 250

    sick 96 250 Rookie Damn Yankees DRN Member

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    Why are you splitting the cases? Last thread you made was asking us why your bike is reving like crazy, did you ever find out why exactly, did you try all the methods we told you to use to find an air leak or anything?

    If you are splitting the cases just to do the seals, you don't need to, you can get to them by taking off the flywheel and pulling apart the clutch side, it sits behind the one gear.

    Just curious cause it seems like you are doing everything but actually tracking down the original problem you were having. And sure, they look like the seals you would need
  3. whenfoxforks-ruled

    whenfoxforks-ruled Old MX Racer

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    They look like the complete seal kit, but, its from K&S Technologies, Inc. Not Suzuki? Some of these off brands are out of china, not for sure about this company. At which point, they are not worth the 4 dollars for shipping. http://www.bikebandit.com/suzuki-motorcycle-rm250w-1998/o/m6601, part number 14&15. If the main crank bearings, or crank is bad, it will not last long.
  4. 1998RM250

    1998RM250 Rookie DRN Member

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    yeah i replaced the head gasket and reed gasket with no success, its sucking oil from the tranny which tells me it's a crank seal at the least right?
  5. whenfoxforks-ruled

    whenfoxforks-ruled Old MX Racer

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    Yep. Check the rod ends for up and down play, bad main bearings, check the big end bearing visually and with a feeler gauge, the thrust washer clearance. And there should be no up and down play in the rod. If it all checks out, try putting screws into the seal and yank them out, no case splitting needed.
  6. 1998RM250

    1998RM250 Rookie DRN Member

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    Yeah the rod bearing has no up and down play at all thankgod, well at least I don't have to split the case thankgod!
  7. sick 96 250

    sick 96 250 Rookie Damn Yankees DRN Member

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    did you ever take the carb boot off and inspect for cracks? This also may be stupid but what do you have your floats set at? I thought my buddy threw a rh crank seal because it was spitting oil out everywhere and it ended up being the float height was way off, once adjusted it basically stopped smoking up the place. If it was fine before you did the rebuild I don't see why the seals would be shot now. Are you positive gear oil is your culprit?
  8. 1998RM250

    1998RM250 Rookie DRN Member

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    Yeah i took the boot off, and no sign of any cracks. I'm not sure about the float height, but it was fine before the top end blew. When the piston shattered off a few pieces I put some mineral spirits in the crank for a couple minutes then turned the bike upside down and hosed out the inside of the crankcase and tons of wd40 to get the water out then two stroke lube. I was thinking maybe i damaged the seals or something doing that! I talked to suzuki service dept and they said the cases need to be split to replace the seals properly, i wish i knew someone i could pay to help me out.
  9. 1998RM250

    1998RM250 Rookie DRN Member

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    I know the waterpump seal is really bad by the complete milk after running a minute, but that wouldn't cause any air to leak right?
    For the hell of it, i changed the fluid to atf with this seal saver additive and tried to start it... The bike doesn't want to start and just backfires, man what kind of mess am I getting myself in! :bang:
  10. whenfoxforks-ruled

    whenfoxforks-ruled Old MX Racer

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    Check the cylinder for being flooded. If you had the stator plate off, check that it is fully seated properly and on the mark. If you had the rotor off, check that the key did not shear.
  11. helio lucas

    helio lucas Subscriber

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    you should really split the cases and inspect (this means change) the main bearings. you cannot take all the tinny bits of cracked piston just by wash the bottom end... just one small piece is enough to destroy one bearing. it may not broke at first time you start the engine, but will reduce drastically the life of the bearing... :coocoo:

    when a bike is burning gear oil most of the times it will smell very bad
    you really need that water pump fixed...
  12. 1998RM250

    1998RM250 Rookie DRN Member

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    I haven't pulled the cover off to check the stator yet, I will have to do that. The bike has been sitting on the stand for a few weeks now, and its weird i noticed that oil is actually seeping through the head gasket somehow!
  13. whenfoxforks-ruled

    whenfoxforks-ruled Old MX Racer

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    Do you mean that fuel or coolant/a compression leak has formed a glacier from the head cylinder seal?
  14. 1998RM250

    1998RM250 Rookie DRN Member

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    idk about a glacier lol, but the head gasket is seeping oil somehow?
  15. whenfoxforks-ruled

    whenfoxforks-ruled Old MX Racer

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    What, you never rode in silt, for hours? A thin sticky film, may be normal on a rebuild, just the first run. If you can see it growing, almost running down, you have a compression/coolant loss. Dark plug, sweet smelling exhaust, bubbles in the radiator?
  16. 1998RM250

    1998RM250 Rookie DRN Member

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    I haven't even ran the bike for more than a few minutes due to the air leak somewhere... I just don't see why oil is there in the first place, and the coolant appears to be clean! Now I remember why I sold my last RMX 250, paid a dealer $1200 to rebuild the motor and it blew 5 hours later. "we don't guarantee rebuilds on race motors".
  17. KIWI KDX

    KIWI KDX Rookie DRN Member

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    hey mate i a having the exact same problem, after replacing the crank seals and berings on a mtes RMX250, high reving and sucking the tranz oil into the combustion chamber,

    the only thing i can think of the the moment is, the crank seal on the clutch
    side has a steel collar that slides over the crank and into the crank seal.

    but the crank and inside of the collar are steel to steel, i cannot understand
    how this would crete a good seal!!!!

    did yours have an o-ring also????
    what are your thoughts????
  18. whenfoxforks-ruled

    whenfoxforks-ruled Old MX Racer

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    Do you mean an air leak at the head, and or base gasket seals? Old studs and nuts DO NOT torque the same as new, they do stretch. Replace them, or use the copper spray and torque more? Leak down test will nail where and what is leaking.
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