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  1. #1

    Join Date
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    To Say 1300 or go 1400 big bore ?

    Guys, my rear cylinder seized up on my GP1300r 2004, which has scored the nikasil. So Iíve either got to buy a new 1300 cylinder to fix the problem or go for a 1400 big bore option, buy bigger pistons and have the cylinders bored and re nikasilled, plus the necessary work on the head etc.

    I guess the question is who are the best people to talk to re 1300 BB conversions as the GroupK one was built for 1200s?

    If I stay with the 1300 option is it best to use stock pistons or are there any benefits in going with the pro-x ones ?

    Also there was a link posted sometime back to a karting site that had an excellent right up on diagnosing 2 stroke pistons, seizures, etc. Iíve tried to search for this but no luck. Does anyone know were it is?

    I would like to understand what caused this so I don't end up doing the same thing again.

    Cheers

    Kev


  2. #2
    just GOT TO DO IT! great lakes gpr 1200's Avatar
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    I had HARRY at Group K build a 1390cc big block and It IS very reliable. They are great guys. SO is KERRY. I have talked to them both. They are stand up guys. I went with group K because of lower cost. AN I did not want the power vavles any more. I seen it as two plus plus. no lose. but I'm sure threre is something lost. I do not know. I'm dumb that way .
    This is the http://groupk.com/ .
    I am sure that kerrys are faster. but I think once you break 70mph it has more to do with handling. I know I called harry about speed and he told me to come here.THIS SITE, Ya no crap. .
    Kerry can do the whole thing, Group K are Engine only people. But My ski starts better than it ever did. boom right now! It never did that out of the box!

    Check them both out. I would not SCREW with 1300cc. NAW If your going to do it go 1400cc. and the price of a group k will impress ya.
    Just my opinion.

  3. #3
    spud's Avatar
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    Kev if you are going 1400cc do a sell/swap with someone for 3 1200 cylinders. That will get you three cylinders for big bore and probably about 500 dollars to put towards it.

    I would get the bad cylinder renicked. But if you need to go big I understand.

    Just wanted to give you an option. The engine builders don't care if they take a 1200 to 1400 or a 1300 to a 1400.

  4. #4

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    Thanks for the feedback guys

    this was the the link that I was after, which is usefull for diagnostics.


    http://www.eric-gorr.com/tech/pistonguide.html

  5. #5
    Hydrotoys's Avatar
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    Consider buying a brand new cylinder/piston set for just the rear cylinder. It will be your cheapest/quickest way out...

    but why did it burn up the rear cylinder? Without a root cause, it will happen again.

  6. #6
    HopatcongGPR's Avatar
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    re-nikasil and piston will run under 400 with shipping and possibly gaskets if they are purchased from the correct seller......nothing is cheaper.

  7. #7
    txgp1300r's Avatar
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    the rear cylinder is closest to bottom of hull and the water that always gets into hull, this may be why #3 always seems to be the dead dog on these motors

  8. #8

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    Quote Originally Posted by hydrotoys
    Consider buying a brand new cylinder/piston set for just the rear cylinder. It will be your cheapest/quickest way out...

    but why did it burn up the rear cylinder? Without a root cause, it will happen again.
    Yep thats what I want to know.

    The other two pistons are like

    the perfect brown picture in this url

    http://www.eric-gorr.com/tech/pistonguide.html

    however they do have the Black spots under the pistons with no.3 being the worst.

    "The underside of this piston has a black spot. The black spot is a carbon deposit that resulted from pre-mix oil burning on to the piston because the piston's crown was too hot. The main reasons for this problem are overheating due to too lean carb jetting or coolant system failure."

    So I guess I must have been too lean on the EFI controller.

  9. #9
    Moderator RX951's Avatar
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    Cylinder swap & renick companies
    http://greenhulk.net/forums/showthread.php?t=9614

    The rear cylinder is the easiest to do also...just a tad bit less to dissasemble.

  10. #10

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    Pictures of #2 piston top and #1 bottom, to me the top looks OK and have not previously look into or understood if the black deposits on the underside of the piston means a lean condition. I allways thought it was the condition of the carbon deposits on the piston crown.

    Any thoughts guys as at the moment I would like to work out what caused no 3 to seize. If not its going to be a leakdown test make sure its very rich.

    Also what about the ring blow by, the motor has 100hrs on it, was it time for new rings?
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