T
able 1
Determining the
T
echnical Condition of Engine by major
Noises and Knocks
Point (joint of
parts) wher
e
knocking is
possible
Thermal
condition of
engine
Engine running mode
Zone wher
e
knocking
is
audible
Natur
e of knocks
Conclusion about adequ
acy
for
further
service
Piston pin to
connecting rod
small end
W
arm
Under load
with sudden
change to hig
her
speed
Cylinder
area
Clear sharp metallic
clink
Discontinue motorcycle
operation.
Should knocks
disappear if the
ignition is
retarded, adjust delayed
ignition. If this does not
help,
remove carbon
deposit
from
combustion
chamber and, if need
be,
replace piston pin, select
ing
one to match the
co
lor marking of
connect
ing
rod small end
.
Piston pin
to piston
boss
Same
Same
Same
Knocking is less clear
and becomes
louder once
engine heats up
Same
Piston to
cylinder
Cold
Idle speed
Same
Brittle
metallic clink
which increases
with spe
ed
variation and becomes
less audible when engine
is warmed
up
.
Similar knocks are
audible when
piston pin
gets seized in connecting
rod small end
Continue operation, if
clink
disappears after
warming
-up of
engine.
When repairing, replace
piston
Discontinue operation.
Replace piston and piston
pin
Connecting
rod big
end
t
o crankpin
Any
At idle speed
and
especially
when
motorcycle
"drags" in
tra
vel
with thrott
le
valve lowered
only
partially
(mino
r engine
speed decrease)
Central por
tion
of engine
crankcase
Dull knocks of medium
volume
Discontinue operation.
Repair the engine
8
Summary of Contents for 750cc Series
Page 1: ...Repair Manual 750cc All Models www imz ural com ...
Page 2: ......
Page 71: ...1 2 3 4 5 6 7 8 Fig 66 Final drive 71 ...
Page 98: ...Fig 11 iring Diagram 9 W 98 ...