APRILIA M191M, Workshop Manual

Page: 97 / 177

ENGINE
3 - 73
Engines M192M / M191M / M245M / M234M / M282M / M281M
• Check the con-rod radial play.
Standard play: 0.036 ÷ 0.054 mm
• Check that axial play holding surfaces are not scored
and use a gauge to check crankshaft width.
NOTE Make sure that the measurement is not altered by the
connection radii with crankshaft bearings.
Standard dimensions: 55.75 ÷ 55.90 mm (125 - 150 cc)
51.40 ÷ 51.45 mm (200 cc)
WARNING
Crankshaft can be re-used if its width is within
the standard values and its surfaces are not
scored.
Shims (200 cc only)
•
Check shim thickness.
Standard thickness: 2.175 ÷ 2.225 mm
• Check shims for scoring
NOTE Refit shims in their original assembly position.
• If the crankshaft axial play is above the standard val-
ues and the crankshaft is not damaged, the problem is
due to wear or to faulty crankcase machining.
•
Check diameters of both bearings of the crankshaft.
Shafts are classified into two categories: Cat. 1 and
Cat. 2, as shown in the table below.
Standard diameter
Cat.1
28.994
÷
29.000
Cat.2 29.000 ÷ 29.006