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Project Bumblebee - Gixxer250

Discussion in 'Your 250cc Projects' started by kiffsta, Feb 14, 2016.

  1. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    I think it could be a bit more serious , 120,20,25 and 140. Will know more on Monday
     
  2. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Measure the clearances before you pull the whole thing apart, see if your compression readings correspond to clearances. Maybe do a leakdown test if you have the equipment to do so.
     
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  3. risky

    risky risky

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    try a shot of oil down each plug hole and retest to see if they improve.

    if goes up could be stuck rings
     
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  4. Frankster

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

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    Nah, I seem to recall doing a leakdown test on this motor with Chris and confirming the rings are effed. Am I remembering that right?
     
  5. risky

    risky risky

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    hope the bore has not been bellied out.
     
  6. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    Not this one frank, she has been at home for a long time, I am assuming it is like the zxr400 where the rings have bound up from sitting. I will get the motor apart on Monday and check the bore , If it is savable, then I might get BK performance to to bore it 1mm oversize and slip some Chinese pistons in. I’d like to get this one sorted for our next ride. If all else fails, I will find an across / bandit 250 engine and use the gsxr250 head on it like @Boydie77 did
     
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    Last edited: Jul 7, 2018
  7. ShaneP

    ShaneP Well-Known Member Premium Member Contributing Member

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    Oh no. If it ran fine before being parked, then sounds like the rings are stuck. Hope you haven't pulled it apart, yet. You could use petrol, wd40, kero or something similar to free them up. Unless the valves are rusted/burnt..
     
  8. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    The engine came apart very easily, it was puzzling as several of the cam retainer bolts were quite loose. The rings were not bound as first thought. The barrels do have wear are very very smooth, I have sent them off to BK performance to be checked and measured to determine if a simple hone or a re-bore is required. I am now pulling the head down to check the valves, I pulled the inlet valves from cylinder 1 and can only assume the previous owner pulled them down before I bought the bike, look how clean they are.

    IMG_5668 (2).JPG IMG_5677 (2).JPG
     
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  9. Murdo

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

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    Just do the petrol in the port test to see if they are leaking.
     
  10. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    I received some feedback today that the outer 2 pots are just within spec but the inner 2 are out, so it is rebore time.

    I am going to order a set of ahl 0.5 pistons from China
     
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  11. ShaneP

    ShaneP Well-Known Member Premium Member Contributing Member

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    What about an Across cylinders and pistons?
     
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