6-45 POWER UNIT
NOTE:
Oversize oil ring rails have no I.D. mark to distinguish size.
Oil ring outer diameter must be measured to determine size.
(3) Calculate the piston / cylinder clearance
(Clearance equals difference between piston diameter
and cylinder bore measurements).
Piston to cylinder clearance
Standard : 0.020 – 0.040 mm (0.0008 – 0.0016 in.)
Service limit : 0.100 mm (0.0039 in.)
If clearance exceeds service limit, replace piston and / or
cylinder or rebore cylinder.
• Piston
Oversize I.D. mark
0.25 mm 0.25
0.50 mm 0.50
• 1st & 2nd Piston ring
Oversize
I.D. mark
1st ring 2nd ring
N25 2N250.25 mm
N50 2N500.50 mm
• Oil ring
Oversize I.D. mark
0.25 mm White paint
0.50 mm Blue paint
I.D. mark
0.25
or
0.50
I.D. mark
1st, 2nd ring
I.D. mark
Oil ring spacer
Identification of oversize piston / piston ring
Two oversize piston / piston ring components, 0.25mm and
0.50mm, are available.
Oversize piston / piston ring are marked as shown,below.
To Next Page
