Harold Bawlzangya Racing

Crank Rebuild

My first attempt at rebuilding a two stroke crank.  I’m starting with this H-series KDX crank:

CrankRebuild (3)

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A few minutes with a fresh cut-off wheel on the angle grinder:

CrankRebuild (4)

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Remember to press the crank pin from the outside-to-inside.  You don’t want to press the crank pin out so the cut portion has to pass through the crank web:

CrankRebuild (5)

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Using a Pro-X (OEM) crank rebuild kit.  $58 on Amazon:

CrankRebuild (6)

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First step installing the crank pin:

CrankRebuild (7)

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CrankRebuild (8)

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Bearing and washers on:

CrankRebuild (9)

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Because I don’t have a nice jig that ensures nearly perfect alignment like the crank builders do, I pressed the other crank web on in steps.  Once I got it started, I put in on the v-blocks and made adjustments to get the run-out below .001″.  Because the crank pin wasn’t fully seated, these adjustments took very little force. I repeated this partial press/adjustment process a total of three times.  This is what the crank looked like after the 3rd press:

CrankRebuild (10)

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Final press:

CrankRebuild (11)

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Specs on side clearance:

CrankRebuild (2)

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CrankRebuild (13)

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CrankRebuild (12)

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A quick video showing my run-out during part of the process:

 

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