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  1. #1

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    How tight should a new crank be

    I just installed a new hotrod crank into a set of cases and the crank fells tight to me so we removed it and check all the pins. Marked the front pin and bearing, still fells tight. Clean another set of cases and reinstall. Fells a little better but tight. It also fells like it rolls better than seems to tighting up just for a second.
    How tight should this crank be??
    Thanks Mike


  2. #2
    Moderator OsideBill's Avatar
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    It should spin freely with no resistance when the case halfs are bolted together and torqued.
    Last edited by OsideBill; 09-06-2008 at 07:25 PM.

  3. #3

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    You might want to check it without seals in it, new seals can cause a good bit of drag. And also if you have the flywheel on, it can feel like it has tight places due to the magnetic pull of the stator poles.

  4. #4
    correct! either without the seals or well lubed seals! it should spin nicely! I have had to try a few times for some reason to get it right .. However I have put an indicator to my hotrods crank and it was absolutely perfect!
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  5. #5
    Moderator OsideBill's Avatar
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    Quote Originally Posted by ZMANN View Post
    correct! either without the seals or well lubed seals! it should spin nicely! I have had to try a few times for some reason to get it right .. However I have put an indicator to my hotrods crank and it was absolutely perfect!
    Ditto it should still spin well with the seals installed, if it is dragging or hanging there is a problem. Make sure the case journals are clean and all case halves are clean. Bolt holes should also be clean. Lube the seals up dry fit the case halves together, no flywheel and tell us how it turns. If it hangs either your crank or your cases are warped. a test like Zman shows will tell you if the crank is warped.

  6. #6

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    I loosened all the bolts and retorque the cases and it turns fine now but still has some drag. I have installed it in two sets of cases now and get the same results. If I turn it hard and let go it make like one rev and stops. No flywheel at this time. If I finger tight the bolts it turns free but when I torgue it, it has drag. Does this sound right or should I remove it and get a set of v blocks and mike it. This crank is a T&w crank
    Thanks Mike

  7. #7
    TRIPLE PIPES ARE 2-STROKE TURBOS allcool's Avatar
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    Quote Originally Posted by mikel70 View Post
    I loosened all the bolts and retorque the cases and it turns fine now but still has some drag. I have installed it in two sets of cases now and get the same results. If I turn it hard and let go it make like one rev and stops. No flywheel at this time. If I finger tight the bolts it turns free but when I torgue it, it has drag. Does this sound right or should I remove it and get a set of v blocks and mike it. This crank is a T&w crank
    Thanks Mike
    No does not sound right.

    Most diffidently check it for runout

    Are the cases a matched set ?

    allcool

  8. #8

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    Quote Originally Posted by allcool View Post
    No does not sound right.

    Most diffidently check it for runout

    Are the cases a matched set ?

    allcool
    Yes both sets of cases are matched and have been run. One set is 05 and the other 06

  9. #9
    TRIPLE PIPES ARE 2-STROKE TURBOS allcool's Avatar
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    Check it for run out.

    Yamaha manual says, max is .006" at either end, and centers are max .002"

    I like to true it down to under .001" everywhere.


    allcool

  10. #10

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    I removed the crank and checked the run out. WoW this is one f'ed up crank.
    With the v-blocks on the center bearing I can see the end of the crank wobble, I don't need a mic.(flywheel side) Man I have some bad luck. Took 3 weeks to get it and now I have to send it back
    Thanks for everyones help
    Mike

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