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  1. #1

    Exclamation 02 gp1200r help!!!!!

    Hi everyone and thanks for all the help I am about to ask for. I just picked up my first ski the other day with 125hr on it for 1000.00. The guy I picked it up from said that he started it up last season and it started making a horriable banging noise and he shut it down imediatly and it sat for 2 years. I inspected the hull and noticed alot of oil and water sitting in it. I got it to fire up and run today and noticed it ran really rough and also seen the rear oil seal under the back piston was flopping around on the coupler shaft. I quick shut it down to inspect it and realized that was where all my oil mixture was coming from. I did a compression test on all the cylinders and came up with the following from front of ski to rear { 109-118-10}. The cylinder that has 10psi is were the oil seal popped out. Is this what is causing the low compression on the cyclinder or am I going to have to just do a top end rebuild or get a whole new engine? Is the rear seals able to be fixed without a tear down of the whole lower half also? Thank you so much for any help as I am very excited to own my first machine!

  2. #2

    Join Date
    Jan 2006
    Texas City, Texas
    First off, welcome to the forum!

    Sounds like you have got some serious issues with your craft, and it will be a complete tear down. The up side is that since you only have 1000 tied up in it so far then you have a lot of room to put money into it with out getting hurt. You could put 1500 more into it and still be on top. It won't be that much though.

    Where do you live, and perhaps we can get you with someone who knows their way around a 1200 engine. If you want to do it your self, then there is a lot of help here on this forum.

  3. #3
    I live in Hamilton NJ. I used to race motorcross and did tear downs all the time but its been a long time.

  4. #4
    CHICKA WAH WAH bren's Avatar
    Join Date
    Sep 2007
    Cairns, Australia
    your crank seal has nothing to do with your loss of compression. your piston in #3 is g.a.w.n.

    pull the engine out and strip down completely.

    the reason seals blow is usually from an over fuel backfire or simply old and worn out. Sometimes they are even fitted incorrectly.

    the engine is blown, do NOT try to start it anymore, you will only be compounding the problem.

    rebuild engine, carbs and replace oil lines / oil pump (or remove and switch to premix)

    good luck with it.

  5. #5
    Thanks alot for the feedback. I am going to pull it out tomorrow and hopefully there isnt any other damage to it. It has 125hrs on it do you think that the crank would still be good for a rebuild?

  6. #6
    CHICKA WAH WAH bren's Avatar
    Join Date
    Sep 2007
    Cairns, Australia
    It's been sitting for a long time, and one can assume that as it was left with an issue the engine was likely NOT fogged for storage hence will have corrosion on the crank. Strip it out and take a close look at the bearings and all surfaces.

    If OK then you should be up for 3x pistons and a nikasil replate and repair on #3.

    Do the carbs while they are out, not just a kit but proper rebuild and preferably through an ultrasonic cleaner.

    If crank is ok still put new seals on it.

    hope this helps

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