Yamaha NEOS 50 YN50 (2002) [64/161] Inspection and repair

ENG

INSPECTION AND REPAIR

4-13

• If this is outside the specified value change

the piston and the set of rings.

Third step:

• Calculate the clearance of the piston to the

cylinder using the following formula:

• If this is outside the specified value, rectify

or change the cylinder and change the pis-

ton and set of rings.



PISTON RINGS

1. Measurement:

• Lateral clearance Outside specified value



Change the piston and/or rings. Use

a thickness gauge .

2. Install:

• Piston rings on the cylinder

Press the ring and the piston crown

together.

Size of the piston P

Standard 39.952 ~ 39.997 mm

1st Clearance 40.25 mm

2st Clearance 40.50 mm

Clearance of piston to cylinder =

Inner diameter of cylinder “C” –

Diameter of piston skirt “P”

Cylinder-piston clearance

0.034 ~ 0.047 mm

Limit

0.1 mm

Standard Limit

Top ring 0.03~0.05 mm 0.10 mm

Second ring 0.03~0.05 mm 0.10 mm