Inspecting The Small End; Inspecting The Wrist Pin; Inspecting The Piston - PIAGGIO MSS Fly 50 4T Workshop Manual

MSS Fly 50 4T

Inspecting the small end

- Measure the internal diameter of the small end
using an internal micrometer.
N.B.
IF THE DIAMETER OF THE ROD SMALL END EXCEEDS
THE MAXIMUM DIAMETER ALLOWED, SHOWS SIGNS OF
WEAR OR OVERHEATING REPLACE THE CRANKSHAFT
AS DESCRIBED IN THE "CRANKCASE AND CRANK-
SHAFT" CHAPTER".
Characteristic
Max. diameter admitted: check the small end
13.030 mm
Standard diameter: check the small end
13 +0.025+0.015mm

Inspecting the wrist pin

- Measure the outer diameter of the gudgeon pin.
Characteristic
Standard diameter: gudgeon pin
13 -0-0.004mm
Minimum admissible diameter gudgeon pin
12.990 mm

Inspecting the piston

- Calculate the piston pin coupling clearance.
Fitting clearance
Pin coupling clearance
0.014 mm
- Measure the outside diameter of the piston, perpendicular to the gudgeon pin axis.
- Carry out the measurement at 27 from the piston crown as shown in the figure.
- Carefully clean the sealing rings housings with the aid of an old piston ring.
13 +0.010+0.005mm 0.005 ÷
Engine
ENG - 87