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Help Suzuki GSF250 GJ74A Cylinder

Discussion in 'Suzuki 250cc In-line 4's' started by Hobeutsss, Oct 6, 2021.

  1. thebeefsalad

    thebeefsalad Well-Known Member

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    smells like oversize codes (.5mm increments if I had to guess), might search for that bike on cmsnl and see what they have to say (specifically in the pistons/rods section)
     
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  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    As it says in the parts book, the first entry of each size is for engine numbers up to 127335, and the second for engine numbers 127336 and above.
     
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  3. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    The correct thing to do is to measure the bore clearance first. Fitting new pistons for no reason at all is a waste of time and money.
     
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  4. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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  5. Hobeutsss

    Hobeutsss Active Member

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    But is there a difference in the pistons? Based on the dimension I didn't see any difference.
     
  6. Hobeutsss

    Hobeutsss Active Member

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    Yes but I still would like to replace the pistons and valves as well. So it would be much more easier to bore it and use oversized pistons
     
  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    No reason to replace pistons and valves if they are within service limits, it is also going to become a very expensive project
    https://www.christensensmotorcycles.com.au/part/suzuki/1291111D10#content
    https://www.christensensmotorcycles.com.au/part/suzuki/1291211D00#content

    That's $640AUD just in valves

    Then ~$300AUD in pistons
    https://www.christensensmotorcycles.com.au/part/suzuki/1211106C02#content

    Then ~$300AUD in piston rings
    https://www.christensensmotorcycles.com.au/part/suzuki/1214005C00#content

    Oversize piston and ring sets are ~$600AUD

    It's getting really expensive really quickly without actually knowing if your parts need replacing

    I'd say investing in two decent micrometers 0mm-25mm and 25mm-50mm to measure what you have would be a good first step
     
  8. Hobeutsss

    Hobeutsss Active Member

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    Well I was expecting to have replace a lot of thigs and that it will get quite costly. I ordered placed and paid already for the cylinders , which was an 500EUR order (I don't know what happens when you send that currency to the land down under) , however , probably, they will not have them in stock. As it goes with Christensensmotorcycles they don't provide shipping, so it will be a bit tricky to get the parts, but will see. Anyways , thanks for the information.
     
  9. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I was only using Christensen motorcycle as examples of prices - I suspect that is parts are available somewhere like impex or cmsnl would ship to you easily

    It would be a shame to replace good parts as that will leave you with less money for parts which might need replacement - it is a very easy trap to fall into
     
  10. Hobeutsss

    Hobeutsss Active Member

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    It's okay, I will order basically everything that I can and then put it back together. Pictures coming soon!
     
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