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  1. #1

    Join Date
    Jun 2009
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    Shawano WI
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    crankshaft index

    Alright I have fried 3 pistons in the PTO cylinder of my SL750. So am looking at all possible issues. I hydro locked the ski a month ago and cracked the PTO piston.
    After I got TDC on the mag piston I used the caliper method to measure the pistons of cylinder 2 and 3. I measured 0.14in and the book says it should be 0.08in. It shows it off 0.06in. Is this method accurate? If it is what are my options now.


  2. #2
    The method is accurate enough to tell you if you need to have a better look at your crank index. Measuring .140" I would say yes, you need to check it further. I have a method that is more accurate than the caliper method and requires both calipers and a dial indicator and can probably write something up for you or you can check it with an degree wheel.
    Last edited by pseudonym; 07-19-2009 at 04:40 PM. Reason: degree not index wheel

  3. #3
    1FASTXC's Avatar
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    Mar 2007
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    Wisconsin
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    Dial indicator and a degree wheel is the most accurate way. The caliper method is only good for a rough idea, too many variables that way to be accurate.

  4. #4

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    Jun 2009
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    Shawano WI
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    I am working on pulling the motor now, so I can look at the flywheel.

  5. #5

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    Jun 2009
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    Shawano WI
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    ok got the motor out and did the degree wheel test and it shows that piston number 3 looks to come to TDC at 115 degrees or so. How do I get this fixed?

  6. #6
    Did you check it at TDC or .100" after TDC?

    If it is out more than ±2° then you need to have a reputable shop rework / rebuild your crank. I don't have any first hand experience with a rebuilt crank but I am sure others here will help you locate a good shop.

  7. #7

    Join Date
    Jul 2008
    Location
    England.Great Britain . UK
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    276
    hi had same trouble with genesis, search { piston melt }. if you split the cases. put top case on wooden blocks lower crank back in. you will see etched on webs no 2 ,3 ,4, 5 . near these is a thin line. with steel rule these should line up, or level them up on case mating surface. my pto webs were out about 10mm. center webs 2mm out. my cranks twisted . spun main bearings some noisy, mag end. holding a collection now for rebuild in uk i am looking at 700 usd.

  8. #8

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    Jun 2009
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    Shawano WI
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    wow I guess I will be trying to find another crank. I have melted 3 pistons in the PTO cylinder. I could have same some money by looking into this earlier. I checked it off TDC piston number 2 was always are 120 where number 3 was not. It read 115.

  9. #9
    1FASTXC's Avatar
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    Mar 2007
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    Call Jeff at midwest crankshaft 920-434-3630. He might be a little hard to get ahold of right now though, he's been up north putting an addition on his cabin. He was around a couple days last week. I tried getting ahold of him for 5 weeks before he finally got home from up north. Just a heads up on that. Otherwise there are other shops around too. Where you from?

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Oct 2006
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    Cleveland OH
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    If your crank is only out of phase and the bearings are all good, you won't need a rebuild. Just a trueing of the crank.

    Which is MUCH cheaper.....

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