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  1. #1

    Cut off 1inch crankshaft and modifying to a 3/4....

    I cut off the 1 inch shaft, left room to drill hole and tap with a 3/4 tap.
    I have a grade 8 3/4 bolt I mounted into it but when I turn the crankshaft, it is very, slightly crooked when i turn it.

    Any suggestions on how to get it straght after I already drilled and tapped?

    What about set screws to use to keep new shaft bolt from loosenig, would it work?
    Is there any reason this set up might not work? I drilled a 1/4 into the crankshaft that goes into the engine but not past where it rests on the bushing, should I be conserned with a balance problem?
    Thanks

  2. #2
    sounds like you need a new crank.

  3. #3
    Senior Member milo raptors's Avatar
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    Quote Originally Posted by Hent View Post
    sounds like you need a new crank.
    agreed....

  4. #4
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    Could you explain further why you did this before you posted it as a HOW TO question?

    We are here to help you... We cannot help if you do not ask first and await instructions. Find new crankshaft and move ahead with your adjenda...

    Best of luck!

    TT

  5. #5
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    Tell us please???

    Why not turn the shaft down to 3/4 ???

  6. #6
    Banned Strigoi's Avatar
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    Quote Originally Posted by Hent View Post
    sounds like you need a new crank.
    Quote Originally Posted by milo raptors View Post
    agreed....
    that. ....

  7. #7
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    Quote Originally Posted by machinebike View Post
    I cut off the 1 inch shaft, left room to drill hole and tap with a 3/4 tap.
    I have a grade 8 3/4 bolt I mounted into it but when I turn the crankshaft, it is very, slightly crooked when i turn it.

    Any suggestions on how to get it straght after I already drilled and tapped?

    What about set screws to use to keep new shaft bolt from loosenig, would it work?
    Is there any reason this set up might not work? I drilled a 1/4 into the crankshaft that goes into the engine but not past where it rests on the bushing, should I be conserned with a balance problem?
    Thanks
    How much did you cut off? Did you really use a 3/4" tap? If you cut off too much, and now the 3/4" (WOW!) bolt wobbles...you screwed up. LOL.

  8. #8
    Here are pics. looking closelt at the measure stick, you can see after turning engine, slightly off one part of turn. I did not turn enough to see correctly, its about half of one of those notches.
    Attached Images Attached Images
    Last edited by machinebike; 10-20-2009 at 07:43 AM.

  9. #9
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    What would be your next move, if the bolt was straight? What were you trying to accomplish?

  10. #10
    I was doing this to use a 3/4 centr. clutch.

    Next moves are to cut end of bolt off, drill and tap end and put groove in the bolt to hold clutch on.

    Its not crooked by much but enough to make it spin with a slight wobble.

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