19
Check-up & Adjustment of Air Valve Gap
Noise will stem from too big gap of the air valve. However if there is too small gap or even no gap at all,
closing of the valve will be hindered, which will cause burn of the valve and output drop. Therefore, the air valve gap
must be checked period ically.
The gap of the air valve should be inspected and adjusted with a cold engine by the follow ing procedures:
1.Remove the caps of the central hole and the top hole (the ignition timing observation hole)in the left crankcase
cover.
2.Remove the caps of the two air valves on the cylinder head.
3.Insert the “T” key into the central hole of the crankcase cover, jam it against the nut of the flying wheel and
then turm the flying wheel clockwise nutil the engraved “T” mark on the flying wheel alin\gns with the engraved line
on the top of the crankcase cover.Swing the rocking arm slightly.A loose rocking arm(which indicates the existence
of clearance) shows that the piston is in the upper stop position of the compressing t\stroke, where the valve can be
adjusted. A tight rocking arm means thar the piston is in the lower stop position of the compressing stroke, In this
case, continuously turn the “T” key clock wise for 360 degrees until the alignment of those engravd marks, where the
valve can be adjustd ,Afterwards, check the valve gap by inserting a feeler in between the valve adjust ing screw and
the end of the valve.
The specified air valve gap :0.05mm for the intake and exhaust valves respecively.
Brake Checking
(1) pull up the front and rear brakes respectively and check for wear of the brake shoes. If the mark “
Ƹ
” on the
brake drum cover aligns with that “
Ƹ
” on the brake cam, it means that the brake shoes are already worn to the limit
and have to be replaced.
(2) Replacement should be carried out at a designated service center and it is recommended that the parts made
by our company are used therein.
19
heck-u
u
u
u
u
u
u
u
p
p
p
p
p
p
p
p
& Ad
d
j
j
j
j
j
j
ustm
m
m
m
m
m
m
e
e
e
e
e
e
e
n
n
n
n
n
n
n
n
t
t
t
t
t
t
t
t
o
o
o
o
o
o
o
o
f
f
f
f
f
f
f
f
A
A
A
A
A
A
A
A
i
i
i
i
i
i
i
i
r
r
r
r
r
r
r
r
Valve Gap
Noise
w
w
w
w
w
w
w
w
i
i
il
l
l
l
l
l
l
l
l
l
l
l
l
l
l
stem
f
f
f
f
f
rom too b
b
b
i
i
i
i
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
a
a
a
a
a
a
a
p of the
a
i
i
i
i
i
i
i
r valve. Howeve
r
r
r
r
r
r
r
r
i
i
i
i
if
f
f
f
f
f
f
f
t
h
h
h
h
h
h
h
e
r
r
r
e
e
e
e
e
i
i
i
i
s
s
s
s
too small g
g
g
g
g
g
a
a
a
a
a
a
a
a
p
p
p
p
p
p
p
p
or eve
n
n n
n
n
n
n
o gap at
clo
sing of th
e
e
e
e
e
e
e
e
v
v
v
v
v
v
v
a
a
a
a
a
a
a
l
l
l
l
ve w
i
i
i
i
l
l
l
l
l
l
l
l
l
b
b
b
b
b
b
b
b
e h
h
in
n
d
d
d
d
d
d
d
ere
e
e
e
e
e
e
d
d
d
d
d
d
d
d
, which w
w
w
w
i
i
i
i
i
i
i
i
l
l
l
l
l
l
l
l
c
c
c
c
ause burn of the
v
v
v
v
v
v
v
v
a
a
a
a
a
a
a
a
l
v
v
v
v
v
v
v
e
e
e
e
e
a
a
a
a
a
a
n
n
n
n
n
n
d
d
d
d
o
o
o
o
o
o
u
u
u
u
u
u
u
t
t
t
t
t
p
p
p
p
u
t
t
t
t
t
t
d
d
d
d
d
d
d
ro
o
o
o
o
o
o
o
p
p
p
p
p
. T
T
T
T
T
T
T
T
h
h
h
h
h
h
h
erefore, t
t
t
h
h
h
h
h
h
h
h
e
air valve
ga
st be chec
k
k
k
k
k
k
k
e
e
e
e
e
e
e
e
d
d
p
p
p
p
p
p
p
p
e
e
e
e
e
e
e
e
riod icall
y
y
y
y
y
y
y
.
The gap of
t
t
t
h
h
h
h
h
h
h
h
e
e
e
e
e
e
e
e
air
v
v
v
v
a
a
a
a
a
a
a
l
v
v
v
v
v
v
v
e s
h
h
h
h
h
h
h
h
o
o
o
o
o
u
u
u
u
u
u
u
u
l
l
l
l
l
l
l
l
d
d
d
d
d
d
d
d
b
b
b
b
b
b
b
b
e ins
s
s
s
s
p
p
p
p
p
p
p
e
e
e
e
e
e
cted and adjusted with a co
l
l
l
l
l
l
l
d
d
d
d
d
d
d
e
e
e
e
ng
i
i
i
i
i
i
i
i
n
n
n
n
n
n
n
n
e
e
e
e
e
e
e
e
b
b
b
b
b
b
b
b
y th
h
h
h
h
h
h
e
e
e
f
f
f
f
f
f
o
o
o
o
o
o
o
o
l
l
l
l
l
l
l
l
l
l
l
l
l
o
o
o
o
o
o
o
w
w
w
w
w
w
w
w
i
i
i
i
i
i
i
ng
g
g
g
g
g
g
p
p
p
p
p
p
p
r
r
ocedures:
1.Remove
e
t
t
h
h
e caps o
f
f
f
f
f
f
t
t
t
t
t
t
h
h
h
h
h
h
h
e
e
e
e
e
e
c
c
c
c
c
c
e
e
e
e
e
e
n
n
n
n
n
n
t
t
t
t
t
t
r
r
r
r
r
r
a
l
l
l
l
l
l
l
l
h
h
h
ole and the top hole (the ignitio
o
n
n
timing o
b
b
b
b
b
b
b
b
s
s
s
s
s
s
e
e
e
e
e
r
r
r
r
r
v
v
v
v
a
a
a
t
t
t
t
t
i
i
i
o
o
o
o
o
o
o
o
n
n
n
n
n
n
n
n
h
h
h
h
h
h
h
ol
l
l
e)in the left crankc
er.
2.R
R
e
e
m
m
ove the caps of t
t
h
e
e t
t
w
w
o
o
air v
v
a
a
l
l
v
v
e
e
s
s
o
o
n
n
t
t
h
h
e cy
y
l
li
inder he
a
ad
d
.
.
3
3
.
.
Inse
e
r
r
t
t
t
t
he “T
T
” ke
e
y
y
into
o
t
t
h
h
e c
c
e
e
n
n
t
t
ra
a
l
l
h
h
ole o
o
f
f
the
e
c
c
rankca
a
se
c
co
ov
ve
e
r
,
, ja
a
m
m
it a
a
g
g
ain
s
st
t
t
t
h
h
e n
n
u
u
t
t
o
o
f
f
t
t
h
h
e f
f
l
l
y
y
i
in
ng
g
w
w
h
h
e
e
el
th
e
n turm th
h
e flying wheel clockwise nutil the engraved “T” mark on the flying wheel alin\gns with the engraved
li
on
the top of the crankcase cover.Swing the rocking arm slightly.A loose rocking arm(which indicates the existe
nc
of
clearance) shows that the piston is in the upper stop position of the compressing t\stroke, where the valve can
b
ad
j
usted. A tight rock
k
k
k
k
k
i
i
i
i
i
i
i
i
n
n
n
n
n
n
n
n
g
g
g
g
g
g
g
g
a
a
a
a
a
a
a
r
r
r
r
r
r
r
m
m
m
m
m
m
m
m
e
e
e
e
e
a
a
a
a
a
a
n
n
n
n
n
n
n
s
s
s
s
s
s
t
t
t
t
t
t
t
t
h
h
h
h
h
h
h
h
a
a
a
a
a
a
a
a
r
r
r
r
r
r
r
r
the piston is in the lower stop p
p
p
p
p
p
p
o
o
o
o
o
o
o
s
s
s
s
s
s
s
s
i
i
i
i
i
i
i
t
t
t
t
t
t
i
i
i
i
i
i
i
o
o
o
o
o
o
o
o
n
n
n
n
n
n
n
n
o
o
o
o
o
f
f
f
f
f
t
t
t
t
t
t
h
h
h
h
h
h
h
e
e
e
e
e
e
e
c
c
c
c
c
c
c
c
o
o
o
o
o
o
o
m
m
m
m
m
m
m
m
p
p
p
p
p
p
p
ressing stroke, In
th
ca
s
e, continuous
s
l
l
l
l
l
l
l
y
y
y
y
y
y
y
y
t
t
t
t
t
t
t
t
u
u
rn the “T” key clock
w
w
i
i
i
i
i
i
i
i
s
s
s
s
s
s
s
s
e
e
e
e
e
e
e
e
for 360 degrees until th
h
h
h
h
e
e
e
e
e
e
e
e
a
a
a
a
a
a
a
a
l
l
l
l
l
l
l
l
i
i
i
i
i
i
i
gnment of those eng
r
r
r
a
a
a
a
a
a
a
a
v
v
v
v
v
v
v
v
d
d
d
d
d
d
d
d
marks, where
th
val
ve can be a
a
a
a
a
a
a
d
d
d
d
d
d
d
d
j
j
j
j
j
j
j
j
u
u
u
std ,Afterwards,
,
,
,
ch
h
h
h
h
h
h
e
e
e
e
e
e
e
e
c
c
c
c
c
c
c
k
k
k
k
k
k
k
k
t
t
t
t
t
t
t
h
h
h
h
h
h
h
h
e
e
e
e
e
e
e
e
v
v
v
v
v
v
v
v
a
l
l
l
l
l
l
v
v
v
v
v
v
ve
e
e
e
e
e
e
gap by inserting
a
a
a
a
a
a
a
a
f
f
f
f
f
f
f
f
eeler in between the v
v
v
v
v
v
v
v
a
a
a
a
a
a
a
l
l
l
l
l
l
v
v
v
v
v
v
v
v
e
e
e
e
e
e
e
e
a
a
a
a
a
a
a
d
d
d
d
d
d
d
d
j
j
j
j
j
j
j
ju
u
u
u
u
u
u
us
s
s
s
s
s
s
s
t ing screw
a
end of th
e
e
e
e
e
e
e
v
v
v
v
v
va
a
a
a
a
a
a
a
l
l
l
l
l
l
l
l
v
e
e
e
e
.
The spe
c
c
c
c
c
c
c
c
i
f
f
f
f
f
f
f
f
i
i
i
i
i
i
i
i
e
e
e
e
e
e
d
d
d
d
d
d
a
a
a
a
a
a
i
i
i
i
r
r
r
r
v
v
v
v
v
v
a
a
a
a
a
l
l
l
l
l
v
v
v
v
v
v
e
e
e
e
e
gap
p
p
p
p
p
p
:
:
:
:
:
0
0
0
0
0
0
0
0
.0
0
0
0
0
0
0
5
5
5
5
5
5
5
5
mm for th
h
h
h
h
h
h
h
e
e
e
e
i
i
i
i
i
i
i
n
n
take and exhau
s
s
s
s
s
s
t
v
v
v
v
v
v
v
a
a
a
a
a
a
a
l
l
l
l
v
v
v
v
v
e
e
e
e
s
s
s
r
r
r
e
e
e
e
e
s
s
s
s
p
p
p
p
p
p
e
e
e
e
e
e
e
e
c
c
c
c
c
c
c
c
i
i
i
i
i
i
i
v
v
v
v
v
v
e
e
e
e
l
l
l
l
l
l
l
l
y
y
y
y
y
y
y
y
.
rake C
h
h
h
h
h
h
h
h
e
e
e
e
e
e
e
e
c
c
c
c
c
c
c
c
k
k
k
k
k
k
k
k
ing
(1) pull up t
h
h
h
h
h
h
h
h
e
e
e
e
e
e
e
e
fron
n
n
n
n
n
t
t
t
t
t
t
t
t
a
a
a
a
a
a
a
a
nd
r
r
r
r
r
r
r
r
e
e
e
e
e
e
a
a
a
a
a
a
r
r
r
r
r
r
r
b
b
b
b
b
b
r
r
r
r
ak
k
k
k
k
k
k
es r
r
r
r
r
r
e
e
e
e
e
e
e
spectively and check for w
e
e
e
e
e
e
e
a
a
a
a
a
a
a
a
r o
f
f
f
f
f
f
f
f
t
t
t
t
t
t
t
t
h
h
h
h
h
h
h
h
e
b
b
b
b
b
b
b
b
ra
k
k
k
k
k
k
k
k
e
e
e
e
e
s
s
s
s
s
s
s
h
h
h
h
h
h
h
o
o
o
o
o
o
e
e
e
e
e
e
e
s
s
s
s
s
s
s
s
. If t
t
t
t
t
t
t
h
h
h
h
h
h
h
e
e
e
e
mark “
Ƹ
” on
ke drum cover aligns wit
h
h
h
h
h
t
h
h
h
h
h
h
at “
“
“
“
“
“
Ƹ
Ƹ
Ƹ
Ƹ
Ƹ
” on the brake cam, it means th
h
a
a
t the bra
k
k
k
k
k
k
k
e
e
e
e
e
e
s
s
s
s
s
s
s
h
h
h
h
o
o
o
o
o
o
o
e
e
e
e
e
e
s
s
s
s
s
s
s
are already worn to the li
have
e
t
t
o
o
b
b
e replac
c
ed
d
.
.
(2) R
R
e
e
p
p
l
l
a
a
cement should
d
b
b
e
e
c
c
a
a
r
r
r
r
i
i
e
e
d
d
o
o
u
u
t
t
at
t
a
a
des
s
i
i
g
g
n
n
a
a
t
t
ed se
e
r
r
v
v
i
i
c
c
e center and it i
i
s
s
r
r
eco
o
m
m
m
m
e
e
n
n
d
d
e
e
d
d t
th
h
a
a
t
t
t
t
h
h
e
e
p
p
a
a
r
r
t
t
s m
our compa
a
ny are used therein.
Summary of Contents for XT50Q
Page 4: ...4 III PARTS SUBASSEMBLIES 4 ...
Page 5: ...5 5 ...
Page 6: ...6 6 ...
Page 7: ...7 7 ...
Page 8: ...8 IV O PERATION 8 ...
Page 28: ...28 9 ELECTRICAL DIAGRAM ...
