mxu 400 Manuel atelier : Page 69

          10. Remove the secondary drive gear/secondary               NOTE: Continue to remove, measure, and install
    driven gear retaining nut. From inside the crank-      until backlash measurement is within tolerance.
    case using a rubber mallet, drive out the output       Note the following chart.
    shaft assembly. Account for the output shaft, a
    shim, a washer, and the nut.
                                                               Backlash Measurement           Shim Correction
                AT THIS POINT                              Under 0.05 mm (0.002 in.)      Decrease Shim
                                                                                          Thickness
To service crankshaft assembly, see Servicing Cen-
                                                           At 0.05-0.33 mm                No Correction Required
ter Crankcase Components sub-section.                      (0.002-0.013 in.)
                                                           Over 0.33 mm (0.013 in.)       Increase Shim
                                                                                          Thickness

   Servicing Center                                        Checking Tooth Contact
Crankcase Components
                                                             NOTE: After correcting backlash of the second-
                                                           ary driven bevel gear, it is necessary to check
  NOTE: Whenever a part is worn excessively,               tooth contact.
cracked, damaged in any way, or out of tolerance,
replacement is necessary.                                   1. Remove the secondary driven output shaft assem-
                                                               bly from the left-side crankcase half.
SECONDARY GEARS

  NOTE: When checking and correcting secondary
                                                            2. Clean the secondary driven bevel gear teeth of old
                                                               oil and grease residue.                                3
gear backlash and tooth contact, the universal              3. Apply a thin, even coat of a machinist-layout dye
joint must be secured to the front shaft or false              to several teeth of the gear.
measurements will occur.
                                                            4. Install the secondary driven output shaft assembly.
Checking Backlash                                           5. Rotate the secondary driven bevel gear several
                                                               revolutions in both directions.
  NOTE: The rear shaft and bevel gear must be
removed for this procedure. Also, always start with         6. Examine the tooth contact pattern in the dye and
the original shims on the rear shaft.                          compare the pattern to the illustrations.
 1. Place the left-side crankcase cover onto the
    left-side crankcase half to prevent runout of the
    secondary transmission output shaft.
 2. Install the secondary driven output shaft assembly
    onto the crankcase.
 3. Mount the indicator tip of the dial indicator on the
    secondary driven bevel gear (centered on the gear
    tooth).
 4. While rocking the driven bevel gear back and
    forth, note the maximum backlash reading on the
    gauge.
                                                                                                           ATV-0103
 5. Acceptable backlash range is 0.05-0.33 mm
    (0.002-0.013 in.).
Correcting Backlash

 NOTE: If backlash measurement is within the
acceptable range, no correction is necessary.

 1. If backlash measurement is less than specified,
    remove an existing shim, measure it, and install a
    new thinner shim.
 2. If backlash measurement is more than specified,
    remove an existing shim, measure it, and install a                                                     ATV-0105
    thicker shim.

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