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  1. #1

    95 Polaris SLT 750 Piston Sizes

    Hello All. Complete newby so be gentle.
    I've read through many of the previously posted threads looking for the information I need but I'm striking out. I ran a compression test on a recently bought ski and discovered that the piston furthest from the fuel pump definitely needs to be replaced. I'm seeing different terms for different cylinders: PTO cylinder, center cylinder? If anyone has the time or interest, could you please enlighten me as to what these refer to? Also, and more importantly, I am looking to find out what size they are: I'm seeing different sizes on the multiple websites that sell them. I thank any and/or all of you in advance for any help you might offer.


  2. #2
    David Drkvampire2001's Avatar
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    Welcome to the Hulk

    Each cyliinder location has a name, PTO, CEN, MAG


    the PTO or Power Take Off, is at the rear of the ski, closest to the Driveshaft. the Cen or Center, is infact the Center, and the Mag or Magneto, is closest to the front of the ski and the Magneto Stator is infront of it. you can get pistons from John Zigler, he is VERY helpful and knowledgeable you can also use WSM. but before replacing the piston. Why does it need to be replaced? what is the compression? have you detetermed the cause of the failure? the 95 SLT 750 is now 18 years old you need to go threw the fuel system, meaning New fuel lines, triple outlet fuel pump. rebuild the carbs with Genuine Mikuni parts. ALL of these parts can be purchased threw John Zigler he is a member on this site. if you need the rebuild kit JOHN is the guy to buy it from as he wont sell you parts you dont need. and they are actual Mikuni parts.

  3. #3
    I'm trying to narrow down the problem/solution as I go. The ski ran great as soon as I got it home. Had a little trouble starting but I replaced the plugs and that problem seemed to be resolved. A couple times I took it out and it had difficulty getting up on a plane. Threading the throttle until it cooperated seemed to solve the problem both times and once it began running better it continued for the entire ride.
    The last time I had it out, I took it out myself for a good half-hour and it ran great. Idled nice and smooth. Took off without a hitch. I came into the launch and my girlfriend had showed up. I killed the ski and we chatted for a few minutes, I loaded her up, started the ski. We took off, cruised for five minutes and I slowed to make a turn and when I came out of the turn and wanted to get back on it, the engine wouldn't come back to full RPMS.
    Since then: I have cleaned the fuel filter, run a can of SeaFoam through the gas tank, sprayed the carbs with SeaFoam spray numerous times, replaced the choke fuel line that I discovered had a pin hole in it, and I ran the compression test (125, 125, and the third didn't even budge the gauge. I tore the cylinder apart and sure enough the outer rim of the piston is broken. I'll try to attach pictures when I get back home.
    I know now that the piston is in need of changing. I haven't figured out the root cause yet, but I've determined that this is a later summer/fall/winter project for me and I hope to have it running top end by next summer. So, I've got time.
    Let me know what you think or if you've got any other ideas.

  4. #4
    David Drkvampire2001's Avatar
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    so the outer edgers where melted. hrmmmm that could be lean, but usually lean in a fuji burns a hole threw the piston, your gonna wanna check oil lines. have you rebuild the carbs?

  5. #5
    I haven't rebuilt the carbs yet. I'm trying to do all I can to avoid it.
    In the time I did get to run the machine, I put two fresh tanks of gas through it. I bought it with very little fuel in it and filled it up on the way home. I understand the original batch of gas could have enameled the carbs but I'm not sold that it is just a problem with the carbs. I've been reading here and there about fuel pump change that is needed on these models because they tend to burn up pistons. Any insight?

  6. #6
    David Drkvampire2001's Avatar
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    Yes lots of insight.


    Why would you trust an 18 year old fuel system? this degrade, for 100 something dollars in a carb rebuild you will THEN HAVE a reliable ski, just replacing the fuel pump is not enough, it is your choice but you really wanna spend the 50 bucks on the fuel pump put the money into replacing the piston then having the same thing happen? replace all the fuel lines, rebuild the carbs, replace the fuel pump

  7. #7
    The fuel lines do look new. The gentleman I bought it from advised that he rebuilt the engine in the two years that he owned it. Also, I've never rebuilt a carb so not knowing how to do it makes me leery of taking on a project like that myself. Of course I don't have a service manual for the ski and I haven't found any here or on the web for free. I think all of your ideas are what I'll eventually end up doing. Right now it just feels like I'm staring up at a mountain and I want to have it completed right now.

  8. #8
    Tony's Avatar
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    Quote Originally Posted by ejkivl02 View Post
    I know now that the piston is in need of changing. I haven't figured out the root cause yet, but I've determined that this is a later summer/fall/winter project for me and I hope to have it running top end by next summer. So, I've got time.
    Let me know what you think or if you've got any other ideas.
    If you have the time here's what I would do.

    Start a project thread. Do a compression test and then pull the jet pump and motor. With the engine on the bench, check crank phase. Tear the motor down and check the crank bearings. After crank assessment, assemble the lower using new seals. Assuming good compression #'s, hone and re ring two of the cylinders, and buy the appropriate size replacement piston after your machinist has measured your jug. Another option would be a complete top end rebuild. Either way, once the engine is assembled do a leak down test on it.

    Record current adjustment screw settings.Tear down the carbs. Record jet sizes. Either use rebuild kits, one per carb, or replace parts as needed. Thoroughly clean and reassemble carbs. Check and record pop off. Check rest of system (tank, shut off valve, water separator, etc).

    Check jet pump, replace seals at the very least. Check drive shaft, coupler, thru hull bearing, replace as needed.

    Clean hull. Prep hull to install motor.

    At this point you're ready to install a rebuilt motor and fuel system into a clean hull, and mate it to a resealed if not rebuilt pump.

    After tuning, and with regular maintenance, you'll have years of fun and reliable service from this ski.

  9. #9
    BlueFishCrisis's Avatar
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    Where are you located?

  10. #10
    Quote Originally Posted by BlueFishCrisis View Post
    Where are you located?
    Upstate, New York on Lake Champlain. Minutes from the Canadian border.

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