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Crf250x 2005 crank/conrod rebuild

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Hi so I’m having to rebuild my crank. I’ve spilt it, put the new conrod in and pressed it all together. I’ve put the bearing surfaces of the crank shafts in v blocks and the are a few thou out but I’ve found the shaft going to the fly wheel is about 15 thou out? The faces of the crank itself aren’t parallel either. Any advice on what I can do to fix this? Cheers :)


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to split and re assemble a crank is a bit specialized, needing the right equipment. as an engineer with my own business its a service i supply. you may have damaged or distorted the crank wheels. but put the crank between running centers (thasts centers that have bearings in them) on a lathe, (very little pressure) and record the run out with a good clock. (mark with a felt pen) take out and hold in one hand.  it is possible to hit one half of the crank wheel with a copper mallet, to bring it into alignment. with wedges and a press its possible  to true up the faces. keep returning to the lathe and re clocking up what you have done. if you are lucky you may get it right. or take it to a machine shop.


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This is what the CRF250X service manual specs for the crankshaft:


side clearance:    0.30mm - 0.75mm (0.0125" - 0.030")      -   maximum service limit  0.8mm (0.030")

radial clearance:  0.006mm - 0.018mm (0.0002" - 0.0007") -   maximum service limit  0.05mm (0.002")



right hand side              (no tolerance values indicated)    -   maximum service limit  0.03mm (0.001")

 left had side                 (no tolerance values indicated)    -   maximum service limit  0.05mm (0.002")



Edited by mlatour

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