Help ZXR250A Engine Rattle

Discussion in 'Kawasaki 250cc In-line 4's' started by Boydie77, Jun 11, 2015.

  1. Boydie77

    Boydie77 Well-Known Member

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    Hi all hoping you can help, my mate's bike is making a fairly loud rattle, seems to be coming from the valve train side of the motor & is worst around 6k RPM. This motor came from a donor bike with unknown history and this was it's first run. The valve clearances were checked and oil and filter changed, this is all we did to it. The old engine we took out sounded a bit rattly too but this has an extra clack-clack-clack sorta noise. I don't have much experience with the ZXR, hoping some clued up members can please have a listen and advise. We're hoping to have the bike ready for this Sunday...!
     
  2. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    My guess would be cam chain.
     
  3. kiffsta

    kiffsta Senior Member

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    I agree, sounds like the cam chain is hitting the cover, maybe pull the tensioner and make sure its within spec
     
  4. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    cct.jpg
     
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  5. GenericForumName

    GenericForumName Active Member

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    Only thing I can think of that we didn't do once the retaining screw was undone was turn the motor over by hand. Perhaps there was extra slack that wasn't tightened.
     
  6. Joker

    Joker See "about me" for contact details. Contributing Member

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    I know what bottom end knock sounds like on a car but not a sports bike...

    It's similar though. Hope it's not that.
     
  7. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    This is what my dead cam chain sounded like... we measured both the old and new chains side by side. Old one was stretched by 5mm. Tensioner was fully extended.

     
  8. Boydie77

    Boydie77 Well-Known Member

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    Thanks guys, the design of the ZXR tensioner is pretty primitive it appears and the #1 suspect. With no ratchet mechanism & relying on spring tension it has probably sagged after 20 odd years! A manual tensioner would be the way to go, we'll have to take some measurements and try to find or make something to fit. In the meantime he has a couple spare tensioners we can try.
     
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  9. zixxer

    zixxer Well-Known Member

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    there is one available for the gpx250's which are the same design i think.
     
  10. Seapop

    Seapop Well-Known Member Premium Member Contributing Member

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    Any luck on finding a manual tensioner for the zxr?? I'd be interested as mine is turning to custard aswell after close inspection
     
  11. Boydie77

    Boydie77 Well-Known Member

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