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Pinned ZXR250 Valve shim sizes

Discussion in 'Kawasaki 250cc In-line 4's' started by Kirk, Aug 12, 2017.

  1. Kirk

    Kirk Well-Known Member Premium Member

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    This thread is to sort out the mystery of valve shim sizes of the Kawasaki ZXR250 as there are many conflicting reports on the internet whether they use the standard 7.48mm shim or a 7.9mm(8mm) shim. The differences could be a change at a certain date, difference between A and C models or the Malaysian spec could be different.

    My current bike is a 1992 ZXR250C complied in 1998 and uses a 7.9mm shim. See photos below for compliance date, engine number, picture of shim sitting on valve, and shim measurement.

    If anyone else gets a chance with a different year/model/spec ZXR250 can you please add similar so we can have this recorded for future?

    6MxF7ZZ.jpg
    qGtuYsk.jpg
    oPWZO7F.jpg
    bapiEbF.jpg
     
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  2. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    1999 built 2003 imported Malaysian ZXR250C
    Frame number ZX250CC11972
    Engine number ZX250CE001935

    Shim size confirmed as 7.9mm
     
    Last edited: Sep 15, 2018
  3. aarondugs

    aarondugs Active Member

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    hey mate, both my 1989 A models use 7.48 shims, quite interesting that yours has 7.9, haven't come across that before
     
  4. Kirk

    Kirk Well-Known Member Premium Member

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    As it's an odd size I'm just wondering if over the years people have replaced with 7.48mm when they check the valve clearances? The only way to confirm would be to look at the shim sitting on the valve and see if it moves around a bit. The 7.9mm shims (precisionshims lists them as 8mm) are an exact fit.
     
  5. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Appears I am wrong. Had shims out of my spare motor today and measured them with the micrometer. 7.85mm diameter. Engine number on this one is ZX250AE014683
     
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  6. Kirk

    Kirk Well-Known Member Premium Member

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    So at least some of the A series had them as well. That just makes it more confusing and possibly not year related.
     
  7. stevodude

    stevodude Active Member Premium Member Contributing Member

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    all I see on ebay, and on sites is 7.48mm, need 8mm or 7.9mm shims.

    Going to give the valves a bit of a lap, (head and cams are out), didn't measure the gaps before pulling it apart.
    it would be so much easier to have a full set, and change the lot out in one hit, rather than guess after valve lap, and need to get a few smaller sizes I am betting.

    so question is:
    1. So any idea where to get a valve shim kit?
    or
    2. will the 7.5mm shims work ok, noting that there will be a bit of size slop that the holder is just a smidge over 8.00mm
     
  8. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Use the correct size shims for your cylinder head. I would not use 7.48mm shims in place of 7.9mm shims, it's asking for trouble.

    You can try finding hot cams shim kits or order exactly what you need from www.precisionshims.com.au - they are pricey but very fast.
     
  9. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    This is an interesting thread. I order my shims from Precision Shims and Chris has always maintained that the 7.48mm shims are correct for my engines. I have asked repeatedly for 7.9mm, but am told the 7.5 (7.48) are fine. There is a bit of slop as @stevodude suggested. Now that you guys have measured and confirmed the 2 sizes, I will go back to Precision Shims and see what Chris says about making 7.9mm shims. Good work gents.
     
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  10. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    I pulled my bike apart today, in preparation for fitting new rings. I checked the valve clearances again and found that the exhausts had tightened somewhat. I also measured the diameter of every shim and confirmed that my ZXR250-C2 engine uses 7.9mm shims... with the added bonus off a few in there being 7.48mm - oops.

    E5eFBAo.jpg

    knn7v8W.jpg
     
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  11. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    Ha ha...you have all bases covered.

    I spoke to Chris at Precision Shims and he wants to see a shim holder for a 7.9mm shim. If we provide one, he'll start making 7.9mm shims. I will look for one when I'm back in Melbourne, unless someone has one off a head?
     
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  12. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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  13. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Chris at precision shims got back to me, he said he has batches of 7.91mm / 7.95mm / 7.98mm shims. I'm going to use the 7.91mm ones
     
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  14. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    yep, I have one, who wants it ?
     
  15. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Chris at precision shims wants a shim holder for the ZXR's so he can make proper sized shims for them, I figured your grenaded motor would be good to get one from
     
  16. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    I dug through all the ZX250A/C parts diagrams on megazip looking at the valve retainers. There are several different part numbers, only one is still available for purchase

    ZX250A1 - 12009-1063 (Discontinued)
    ZX250A2 - 12009-1066 (Discontinued)
    ZX250C1/C2/C3/D1 - 12009-1063 (Discontinued)
    ZX250C4 - 12009-1077 (Available)
    ZX250C5 - 12009-1077 (Available)
    ZX250C7 - 12009-1077 (Available)
     
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  17. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    @kiffsta you'll need to check if the holders in that engine take 7.9mm shims. I'll see you on Thursday, so we chat/check then if you're busy.
     
  18. sharky

    sharky Well-Known Member Premium Member

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    I have some spare shim holders already apart @Frankster , both the A & C holders seem to measure a few thous over 8mm.
     
  19. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    That's what I thought too, but since I was told 7.5mm (7.48mm) were correct, by a shim manufacturer, I never really questioned it. The first time I ordered from Precision Shims I actually asked for 8mm shims and was told that 7.5mm was the correct size. I've been using them in all my ZXR engines, so from now on I'll be ordering 7.91mm shims to fill the holder better.
     
  20. Unkepttoenails

    Unkepttoenails Demented

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    Not sure on the format of my reply should be but my c1 zxr has 7.85 mm shims if that's any help to y'all. I'm using 7.48 in the engine now when I get it going
     

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