Engine

Checking the crankshaft

~1min read

1. Measure:

  • Crankshaft runout Out of specification Replace
    the crankshaft, bearing or both.

NOTE:

Turn the crankshaft slowly.


Checking the crankshaft

2. Measure:

  • Big end side clearance Out of specification Replace
    the crankshaft.

3. Measure:

  • Crankshaft width Out of specification
    Replace the crankshaft.

3. Measure:

  • Crankshaft width Out of specification Replace the crankshaft.

4. Check:

  • Crankshaft sprocket Damage/wear Replace the
    crankshaft.
  • Bearing Cracks/damage/wear Replace the
    crankshaft.

5. Check:

  • Crankshaft journal Scratches/wear Replace the
    crankshaft.
  • Crankshaft journal oil passage Obstruction Blow out with
    compressed air.

Test yourself

A quick Yamaha YZF-R125 quiz: every answer comes with an explanation and a link to the manual page.