5-36 ENGINE TOP END
If a new piston or cylinder is used, check piston to cylin-
der clearance (see Piston/Cylinder Clearance), and use
new piston ring.
Replace the cylinder base gasket with a new one.
Be sure to install the dowel pins [A].
Install the front cylinder in the same way.
Position the front piston at TDC.
Cylinder Wear Inspection
Since there is a difference in cylinder wear in different di-
rections, take a side-to-side and a front-to-back measure-
ment at each of the 3 locations (total of 6 measurements)
shown in the figure.
If any of the cylinder inside diameter measurements ex-
ceeds the service limit, replace the cylinder.
10 mm (0.39 in.) [A]
60 mm (2.4 in.) [B]
20 mm (0.79 in.) [C]
Cylinder Inside Diameter
88.000 ∼ 88.012 mm (3.4646 ∼ 3.4650 in.)
Service Limit: 88.10 mm (3.468 in.)
Piston Wear Inspection
Measure the outside diameter [A] of each piston 5 mm
(0.20 in.) [B] up from the bottom of the piston at a right
angle to the direction of the piston pin.
If the measurement is under service limit, replace the pis-
87.955 ∼ 87.970 mm (3.4628 ∼ 3.4634 in.)
Service Limit: 87.80 mm (3.457 in.)
Piston/Cylinder Clearance Inspection
Subtract the piston diameter from the cylinder inside di-
ameter to get the piston/cylinder clearance.
0.030 ∼ 0.057 mm (0.0012 ∼ 0.0022 in.)
If the piston/cylinder clearance is less than the specified
range, use a smaller piston or increase the cylinder inside
diameter by honing.
If the piston/cylinder clearance is greater than specified
range, use a larger piston.
If only a piston is replaced, the clearance may exceed
the standard slightly. But it must not to be less than the
minimum in order to avoid piston seizure.