tolerance, the cylinder block need not be bored.
However, in no case should the piston/cylinder
clearance be less than the minimum.
Piston Ring Inspection
Measure the top 2 rings for wear by inserting
each into the bottom of the cylinder where the
cylinder is least worn. Seat the ring squarely in
the cylinder by pushing it in slightly with the
top of a piston. Measure the installed end gap
with a feeler gauge (Figure 72). A new ring's gap
should be no smaller than the limit in Table 1.
If the gap is smaller than specified, hold a
small flat file in a vise, grip the ends of the ring
with your fingers and enlarge the gap to the
required minimum (Figure 73). As old rings
wear, the gap will increase. Discard any rings
whose installed gap exceeds the limit in Table
1. Always install new rings when installing new
pistons or when you have any doubt about the
condition of the rings.
Roll each ring around in its piston groove to
make sure there is no binding (Figure 74).
Check the side clearance of each ring with a
feeler gauge (Figure 75). Refer to Table 1. If the
clearance is incorrect, replace the pistons, rings
Connecting Rod Inspection
After removing the pistons, the connecting
rods can be inspected without removing them
from the engine.
1. Measure the ID (inside diameter) of the
small end of the connecting rod with a snap
gauge and micrometer (Figure 76). If the ID is
larger than the limit given in Table 1, install a
new c o n n e c t i n g r o d ( s e e Crankshaft
Disassembly in this chapter).
2. Check the rod for obvious damage such as
cracks and bums.
3. Check connecting r o d big-end side
clearance with feeler gauges (Figure 77). If the
clearance exceeds the limit in Table 1, replace
the connecting rod. Ifthe clearance still exceeds
the wear limit with a new connecting rod, the
crankshaft should be replaced.
4. Check the connecting rod big-end radial
(up-and-down) clearance; you can make a
preliminary inspection by turning t h e
crankshaft until the crankpin is at TDC (top
Ifthe crankshaft must be rotated, pull up
on the cam chain and keep it taut while
turning the crankshaft. If the chain is
slack, it may jam up at the crankshaft
and damage the chain and the sprocket.
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