Inspecting The Small End; Inspecting The Piston - PIAGGIO NRG Power Purejet Workshop Manual

NRG Power Purejet

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 AL-
LOWED, SHOWS SIGNS OF WEAR OR OVER-
HEATING REPLACE THE CRANKSHAFT AS
DESCRIBED IN THE "CRANKCASE AND
CRANKSHAFT" CHAPTER".
Characteristic
Rod small end: standard diameter
17 +0.011-0.001
Rod small end: maximum allowable diameter
17,060 mm
Inspecting the wrist pin
- Check the wrist pin external diameter using a mi-
crometer
Characteristic
Wrist pin: standard diameter
12 +0.005 +0.001 mm

Inspecting the piston

- Measure the bearings on the piston using a bore
meter
- Calculate the piston-pin coupling clearance.
Characteristic
Wrist pin housing: standard diameter
12 +0.007 +0.012
Wrist pin housing: standard clearance
0.002 ÷ 0.011 mm
Engine
ENG - 21