ZONGSHEN CBS300 User manual

共50 页第1页
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CBS300 发动机
维修手册
CBS300 Engine
Maintenance Manual
编制：
Prepared by:
校对：
Checked by:
审核：
Reviewed by:
批准：
Approved by:

共50 页第2页
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主要性能技术参数
Main Technical Parameters
项目
Item
规格
Specification
发动机
Engine
型号
Model number ZS174MN-3
型式、汽缸数
Type and number of
cylinders
单缸、水冷、四冲程、顶置单凸轮式
Single-cylinder, water-cooling,
four-stroke, single overhead camshaft
缸径×行程
Bore × stroke φ74×65mm
汽缸工作容积
Displacement 279.5ml
压缩比
Compression ratio 10.2~10.7：1
化油器形式
Carburetor type
真空膜片式
Vacuum membrane
空气滤清器
Air filter
纸滤芯
Paper filter element
润滑方式
Lubrication method
压力+飞溅
Pressure + splash
起动方式
Starting method
电起动
Electric
最大功率/相应转速
Max. power/corresponding
speed
18.5(1±5%)kW/8500(1±5%)rpm
最大扭矩/相应转速
Max. torque/corresponding
speed
22(1±5%)N.m/7000(1±5%)rpm
怠速
Idle speed 1400±100 r /min
传动系统
Transmission System
离合器
Clutch
手动湿式多片式
Manual wet multi-plate
变速器
Transmission
常啮合两级传动六档变速
Constant mesh, two-stage
transmission, 6-speed gearshift
变速方式
Gearshift method
左脚操纵往复式
Reciprocating operation by left foot
初级减速比
Primary reduction ratio 3.091
齿轮速比
Gear ratio
第1档
1st gear 2.58
第2档
2nd gear 1.86
第3档
3rd gear 1.44
第4档
4th gear 1.16
第5档
5th gear 1
第6档
6th gear 0.857

共50 页第3页
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项目
Item
规格
Specification
点火系统
Ignition System
点火方式
Ignition method
电容储能式
Capacitor discharge
火花塞
Spark plug CR8EB
火花塞间隙
Spark plug gap 0.7mm-0.8mm
油料
Fuel
燃油牌号
Fuel grade ≥RQ90
发动机机油
Engine oil
规格
Specification SJ 10W/40
容量
Capacity 1.3L

共50 页第4页
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汽缸头和气门
Cylinder Head and Valve
维修须知
Maintenance instructions
故障排除
Troubleshooting
汽缸头盖的拆卸
Removal of cylinder head cover
汽缸头的拆卸
Removal of cylinder head
汽缸头盖的分解
Disassembling of cylinder head cover
气缸头的分解
Disassembling of cylinder head
气门和气门弹簧的检查
Inspection of valve and valve spring
摇臂及摇臂轴的检查
Inspection of rocker arm and rocker arm shaft
凸轮轴部件的检查
Inspection of camshaft components
汽缸头的检查
Inspection of cylinder head
气门座的检查、研磨
Inspection and grinding of valve seat
气门导管的检查
Inspection of valve guide
气门导管的更换
Replacement of valve guide
测量气门座接触面的宽度
Width measurement of valve seat contact
surface
汽缸头的组装
Assembling of cylinder head
气缸头盖的组装
Assembling of cylinder head cover
汽缸头的安装
Installation of cylinder head
气缸头盖的安装
Installation of cylinder head cover
维修须知
Maintenance Instructions
注意事项：
Notes:
● 凸轮轴是由缸头上油道孔供油润滑的，缸头上的油道绝对不能有异物进入，并保持畅通。
The camshaft is lubricated with oil supplied through the cylinder head oil passage hole,
which shall never have foreign matters and shall be kept unblocked.
● 在安装汽缸头之前，缸头定位销一定要装配好。
Before installation of cylinder head, the cylinder head dowel pins shall be well assembled.
● 凸轮轴不能有划伤痕迹，装配时先打上机油。
The camshaft shall have no scratch marks and be applied with oil before being assembled.
各部件维修参数
Maintenance parameters of components
项目
Item
标准值 mm
Standard Value
(mm)
维修极限值 mm
Maintenance
Limit Value (mm)
摇臂与缸头盖摇臂开档的轴向间隙
Axial clearance between rocker arm and cylinder
head cover
0.05～0.3 0.5

共50 页第5页
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项目
Item
标准值 mm
Standard Value
(mm)
维修极限值 mm
Maintenance
Limit Value (mm)
摇臂与摇臂轴的径向间隙
Radial clearance between rocker arm and rocker arm
shaft
0.016～0.045 0.08
气门间隙
Valve clearance 0.02～0.04 ------
凸轮轴基圆跳动
Camshaft base circle run-out 0.02 0.04

共50 页第6页
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项目
Item
标准值 mm
Standard Value
(mm)
维修极限值 mm
Maintenance
Limit Value (mm)
气门
Valve
气门杆外径
Outer diameter of
valve stem
进气
Intake φ4.972～φ4.987 φ4.96
排气
Exhaust φ4.96～φ4.975 φ4.94
气门导管内径
Inner diameter of
valve guide
进气
Intake φ5～φ5.015 φ5.025
排气
Exhaust φ5～φ5.015 φ5.025
气门密封带宽度
Width of valve sealing strip 1.5 ----
汽缸头
Cylinder head
平面度
Planeness 0.04 0.05
气门座工作面宽度
Width of valve seat working surface 0.8 ----
故障排除
Troubleshooting
缸内气压低：
Low pressure in cylinder:
1、气门
Valve
---------- 气门间隙调整不正确
Incorrect adjustment of valve
clearance
---------- 气门密封不严
Insufficient sealing of valve
---------- 配气正时不对
Incorrect valve timing
---------- 气门弹簧断裂
Breakage of valve spring
2、汽缸头
Cylinder head
---------- 火花塞与汽缸头连接不紧密
Loose connection between spark
plug and cylinder head
---------- 汽缸头垫损坏
Damage of cylinder head gasket
---------- 汽缸头有裂纹或砂眼
Cracks and sand holes on cylinder
head
3、缸体、活塞、活塞环
Cylinder body, piston, piston ring
---------- 活塞环间隙过大或断裂
Excessive clearance or breakage of
piston ring
---------- 活塞有裂纹或过度磨损
Cracks or excessive wear of piston
---------- 缸体内径过大或砂眼
Excessive inner diameter of cylinder
body or sand holes on it
排气有黑烟
Exhaust having black smoke
1、气门导管磨损
Wear of valve guide
2、挡油罩渗漏或损坏
Leakage or damage of oil shield
3、汽缸头垫渗漏
Leakage of cylinder head gasket
4、活塞环间隙过大
Excessive clearance of piston ring
噪音过大或异响
Excessive or abnormal noise
1、气门调整不正确
Incorrect adjustment of valve
2、气门卡住或气门弹簧断裂
Valve getting stuck or valve spring getting
broken
3、上摇臂过度磨损
Excessive wear of upper rocker arm
4、配气正时不准
Inaccurate valve timing
5、凸轮轴磨损
Wear of camshaft

共50 页第7页
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汽缸头盖的拆卸
Removal of Cylinder Head Cover
1、拆下汽缸头盖进气、排气两侧气门室盖的 4
颗GB/T16674 小盘 M6×20 的紧固螺栓。
Remove the 4 small GB/T16674 M6×20
pan-head fastening bolts on intake and
exhaust valve chamber covers of cylinder
head cover.
2、拆下气缸头进气、排气两侧的气门室盖。
Remove intake and exhaust valve
chamber covers of cylinder head.
3、拆下紧固缸头盖的 2颗GB/T16674 小盘螺
栓M6×105、2颗GB/T16674 小盘螺栓
M6×20、1颗GB/T16674 小盘螺栓 M6×32，
1颗GB/T16674 小盘螺栓 M6×28，2颗
GB5789 大盘螺栓 M6×65。
Remove the 2 small GB/T16674 M6×105
pan-head bolts, 2 small GB/T16674
M6×20 pan-head bolts, 1 small
GB/T16674 M6×32 pan-head bolt, 1 small
GB/T16674 M6×28 pan-head bolt and 2
large GB5789 M6×65 pan-head bolts on
cylinder head cover.
注意：
Note:
2颗大盘螺栓各有一铜垫片(φ6.2×2×φ13)。
Each of the 2 large pan-head bolts has a
copper gasket (φ6.2×2×φ13).
4、拆下缸头盖。
Remove the cylinder head cover.
汽缸头的拆卸
Removal of Cylinder Head
1、拆下 NC250 缸头密封胶套，NC250 凸轮轴
档板（形状为半圆环）。
Remove the NC250 cylinder head sealing
bush and the NC250 camshaft baffle
(semicircular).
M6×20
大盘 M6×65
有铜垫
Large M6×65 pan-head bolts
have copper washers.
M6×20
M6×105
M6×28 M6×32
NC250 缸头密封胶套
NC250 cylinder head sealing
bush
NC250 凸轮轴档板（形状为半圆环）
NC250 camshaft baffle
(semicircular)

共50 页第8页
Page 8 of 50
2、拆下 2颗紧固启动电机的 GB5789 大盘螺栓
M6×28，拆下启动电机。
Remove the 2 large GB5789 pan-head
bolts fastening the starting motor, and
remove the starting motor.
注意：
Note:
电机底部靠近废管侧有一颗电机安装座圈，不
要遗漏。
There is a motor mounting seat ring near
the waste pipe side on the motor bottom,
which shall not be omitted.
3、拆下 CB125Z 张紧器密封螺栓 M6×6，拆下
2颗紧固张紧器的 GB70.1 内六角螺栓
M6×16，然后在拆下张紧器，张紧器密封垫。
Remove the CB125Z tensioner sealing bolt
(M6×6), the 2 pieces of GB70.1 M6×16
hexagon socket head bolts fastening the
tensioner, and then the tensioner and
tensioner sealing gasket.
注意：
Note:
避免张紧器上的 O形圈掉落
Prevent the O-ring on tensioner from
falling off.
4、拆下凸轮轴轴承 6201、轴承档板。
Remove camshaft bearing 6201 and
bearing baffle.
5、拆下凸轮轴组合。
Remove the camshaft assembly.
6、拆下 4颗AB 栓螺母 M10×1.25，然后拆下 4
颗平垫圈（10.5×2×20）。
Remove four AB bolt nuts (M10×1.25) and
then remove the 4 flat washers
(10.5×2×20).
7、拆下气缸头。
Remove the cylinder head.
底部有一颗座圈
A
seat ring on the
bottom 大盘 M6×28
Large M6×28 pan-head
bolts
内六角螺栓
M6×16
M6×16 hexagon socket head
bolts
张紧器密封螺栓
M6×6
M6×6 tensioner sealing bolt
凸轮轴轴承
Camshaft bearing
轴承档板
Bearing baffle
A
B栓螺母、垫片
Nuts and washers for AB bolts

Di
s
1、
拆
栓
R
s
h
c
y
注意
：
Note
螺栓
上
Ther
e
2、
拆
2
R
p
a
(
φ
3、
取
R
a
r
r
o
用气
门
然后
放
簧和
气
Use t
h
spring
valve
c
remo
v
and t
h
注
意
Not
e
1.
2.
汽
s
assemblin
g
拆
下缸头盖
上
栓
M14×1。
R
emove the
2
h
aft locatin
g
y
linder hea
d
：
:
上
带有 O形
e
are O-rin
g
拆
下顶部 2
颗
颗铜垫片(φ
R
emove th
e
a
n-head bo
φ
6.2×1×φ1
0
取
下进、排
气
R
emove the
r
m shafts a
o
cker arms.
气
Disassem
b
门
拆卸器将
气
放
松气门拆
卸
气
门。
h
e valve ext
r
and remo
v
c
ollet; then
l
v
e the valve
h
e valve.
意
：
e
:
为了防止气
份的压缩气
即可；
To avoid
p
valve spri
n
excessivel
y
valve colle
t
拆下的全部
零
配时达到原
来
All the pa
r
marked so
original lo
c
汽
缸头盖的
分
g
of Cylind
上
2颗NC2
5
2
pieces of
N
g
plate bolt
s
d
cover.
圈φ9.4×2.
4
g
s (φ9.4×2.
4
颗
GB16674
小
6.2×1×φ10
)
e
2 small
lts and the
0
).
气
摇臂轴，
进
intake an
d
s well as i
n
气
缸头的分
解
b
ling of Cyl
气
门弹簧压
下
卸
器，取下
气
r
actor to pr
e
v
e the valv
e
l
oosen the
v
spring reta
i
门弹簧产生
永
门弹簧，只
需
p
ermanent
n
g, it shall
y
but as m
o
t
can be re
m
零
件均应作
好
来
的装配位
置
r
ts remov
e
as to mou
c
ations dur
共
分
解
e
r Head C
o
5
0摇臂轴定
位
N
C250 roc
k
s
(M14×1)
o
4
。
4
) on the bol
小
盘螺栓 M
6
)
。
GB16674
M
2 copper g
进
、排气摇臂
d
exhaust
n
take and e
x
解
inder Head
，拆下气门
锁
门弹簧座，
气
e
ss down th
e
e
and remo
v
alve extrac
t
i
ners, valve
永
久变形，
不
需
能拆下气
门
deformati
o
not be pr
e
o
derately a
m
oved.
好
标记，确
保
置
。
e
d shall be
nt them to
ing assem
b
共
50 页第
Page 9 of 5
o
ve
r
位
板螺
k
er arm
on the
ts.
6
×18，
M
6×18
askets
。
rocker
x
haust
d
锁夹；
气
门弹
e
valve
o
ve the
t
or and
spring
不
能过
门
锁夹
o
n of
e
ssed
a
s the
保
在装
well
their
b
ling.
9页
0
s
小
盘
Sm
a
铜
垫
φ6.
2
摇
臂轴定位板螺栓
M
M
14×1 bolts for ro
c
s
haft locating plate
盘
螺栓 M6×18
a
ll M6×18 pan-hea
d
垫
片φ6.2×1×φ10
2
×1×φ10 copper w
a
M14×1
c
ker arm
e
d
bolts
a
shers

In
检查
气
损，
测
Chec
k
the v
a
outer
d
value
s
进气：
Intak
e
排气：
Exha
u
接触
面
Maint
e
surfa
c
注
意
Not
e
如
果
门
座
更
换
If t
h
rou
g
con
gua
val
v
Insp
e
检查
摇
隙，
如
隙偏
大
Chec
k
and t
h
any
w
cleara
shall
b
检查
摇
则需
更
Chec
k
seriou
repla
c
气门
和
spection o
f
气
门是否弯
曲
测
量气门杆
外
k
the valve
f
a
lve stem fo
r
d
iameter of
s
:
φ4.96mm
e
: φ4.96mm
φ4.94mm
u
st: φ4.94m
m
面
的宽度维
修
e
nance limi
c
e: 1.5mm
意
：
e
:
果
气门接触
面
座
接触不正
常
换
气门。
h
e contact
g
h, uneve
n
tact with
v
a
rantee the
v
e shall be
r
摇
臂
e
ction of R
o
摇
臂是否有
磨
如
磨损、毁
坏
大
则均需更
换
k
the rocke
r
h
e rocker ar
m
w
ear and d
a
a
nce of roc
k
b
e replaced
摇
臂轴是否
有
更
换新的摇
臂
k
the rocker
s wear, th
e
c
ed with a n
e
和
气门弹簧
的
f
Valve and
曲
、烧伤或气
外
径。维修
极
f
or bending
r
abnormal
w
valve stem.
m
修
极限值：1.
5
t value for
面
很粗糙，
磨
常
，不能保
证
surface
o
n
ly abraded
v
alve seat
,
sealing p
e
r
eplaced.
臂
及摇臂轴的
o
cker Arm
a
Shaft
磨
损、毁坏、
坏
现象严重
或
换
新的摇臂。
r
arm for
w
m
roller for
a
a
mage or f
o
k
er arm roll
e
with a new
o
有
磨损现象，
臂
轴。
arm shaft f
o
e
rocker a
r
e
w one.
共
的
检查
Valve Spri
n
门杆有不正
常
极
限值：
and burnin
w
ear; meas
u
Maintenan
c
5
mm
width of
c
磨
蚀不均匀
或
证
密封性能，
o
f valve is
or in abn
o
,
which c
a
e
rformanc
e
检查
a
nd Rocke
r
摇臂滚轮的
轴
摇臂滚轮的
轴
w
ear and d
a
a
xial cleara
n
o
r excessiv
e
e
r, the rock
e
o
ne.
如果磨损现
象
o
r wear; in
c
r
m shaft s
h
共
50 页第
Page 10 of
5
ng
常的磨
g, and
u
re the
c
e limit
c
ontact
或
与气
均应
very
o
rmal
a
nnot
e
, the
r
Arm
轴
向间
轴
向间
a
mage,
n
ce; for
e
axial
e
r arm
象严重
c
ase of
h
all be
排
气
标
识
Exh
sha
f
10 页
5
0
气
摇臂轴
识
“P”
aust rocker arm
f
t marked with "P"
排气摇
臂
Exhaus
t
arm
进气摇臂轴
标识“J”
Intake rocke
marked with
臂
t
rocker 进
气
Int
a
e
r arm shaft
"J"
气
摇臂
a
ke rocker arm

共50 页第11 页
Page 11 of 50
凸轮轴部件的检查
Inspection of Camshaft Components
1、检查凸轮轴表面是否有磨损、毁坏现象及凸
轮轴两端的轴承转动是否灵活，如磨损现象
严重或轴承转动有发卡的现象，则应更换新
的凸轮轴部件。
Check the camshaft surface for wear and
damage, and the bearing rotation for
flexibility at both ends of camshaft; in case
of serious wear or unsmooth bearing
rotation, camshaft components shall be
replaced with new ones.
2、检查凸轮轴减压阀甩块组合是否有裂纹、破
裂等现象及减压阀离心甩块与减压阀芯轴
是否有松动的现象，如果有则需更换减压阀
甩块组合。
Check the reducing valve flail block
assembly of camshaft for crack and
fracture, and the reducing valve flail block
and spindle for looseness; if any, the
reducing valve flail block assembly shall be
replaced.
汽缸头的检查
Inspection of Cylinder Head
1、检查汽缸头的密封性是否良好，如果缸头的
密封性较差，则应更换新的气缸头和气门。
Check the cylinder head for airtightness;
for poor airtightness, the cylinder and valve
shall be replaced with new ones.
2、检查火花塞孔及气门座是否有裂纹。
Check spark plug hole and valve seat for
any crack.
3、检查汽缸头是否变形，并用刀口尺和塞尺检
查汽缸头的平面度。
Check the cylinder head for deformation,
and check the planeness of cylinder head
with knife straight edge and feeler gauge.
进气门
Intake v valves
排气门
Exhaust valves
火花塞
Spark plug

共50 页第12 页
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气门导管的检查
Inspection of Valve Guide
测量每一根气门导管的内径，并作好记录。
Measure the inner diameter of each valve
guide, and record it.
维修极限值：
Maintenance limit values:
进气：φ5.025 mm
Intake: φ5.025 mm
排气：φ5.025 mm
Exhaust: φ5.025 mm
注意：
Note:
测量气门导管的内径前，应先将导管内的积碳
完全清除干净。
Before the inner diameter of valve guide
is measured, the carbon deposit inside
the pipe shall be completely cleared
away.
若气门导管磨损严重则需要更换缸头。
If the valve guide is heavily worn, the cylinder
head shall be replaced.
测量气门座接触面的宽度
Width Measurement of Valve Seat Contact
Surface
维修极限值：1.5 mm
Maintenance limit value: 1.5 mm
如查气门座太宽、太窄或有凹痕，则应更换气门
及缸头。
If the valve measured is too wide, too narrow or
pitted, the valve and cylinder head shall be
replaced.
汽缸头的组装
Assembling of Cylinder Head
1、将气门弹簧下座、挡油罩装到气门导管上。
Mount the lower valve spring retainer and
oil shield onto the valve guide.
2、将进、排气门杆涂上润滑油后，装入气门导
管，装好气门弹簧、气门弹簧上座及气门锁
夹。
Apply lubricating oil on intake and exhaust
valve stems and mount them in the valve
guide; then mount the valve spring, upper
valve spring retainer and valve collet.

共50 页第13 页
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3、再用气门拆卸器压下气门弹簧，然后将气门
锁夹装入气门弹簧座内。
Press down the valve spring with the valve
extractor, and then mount the valve collet
in the valve spring retainer.
注意：
Note:
1、为防止气门弹簧产生永久形，不能过分地
压缩弹簧，以能装入气门锁夹即可。
To avoid permanent deformation of
valve spring, it shall not be pressed
excessively but as moderately as the
valve collet can be mounted.
2、锁夹需正确卡入气门的环槽内，安装好后
用胶榔头从气门轴向轻搞击气门上座，确
保锁夹安装到位。
Mount the collet properly into the
circular valve groove, and then tap
the upper valve seat slightly and
axially from the valve, to ensure the
collet is mounted in position.
4、对组装好的汽缸头组合进行气密性检测，若
汽缸头组合无泄露则可进行下一步操作。
Carry out the airtightness detection of the
assembled cylinder head assembly; if no
leakage is found, the next step of operation
can be executed.
6、将张紧板安装到缸头上。
Mount the tensioning plate onto the
cylinder head.

共50 页第14 页
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气缸头盖的组装
Assembling of Cylinder Head Cover
先将进、排气摇臂放到缸头盖内，再分别将进、
排气摇臂轴穿过缸头盖和进气排气摇臂轴孔装
配到位，再安装 2颗GB16674 小盘螺栓 M6×18
将摇臂轴紧固，最后将 NC250 摇臂轴定位板螺
栓装到缸头盖上相应的孔中并紧固。
Firstly, put the intake and exhaust rocker arms
in the cylinder head cover, and then put intake
and exhaust rocker arms through cylinder head
cover and intake & exhaust rocker arm shaft
holes respectively to mount them in place;
fasten the rocker arm shafts with 2 small
GB16674 M6×18 pan-head bolts; finally, put
the NC250 rocker arm shaft locating plate bolt
in the corresponding hole on cylinder head
cover and tighten it.
注意：
Note:
1. 装摇臂轴时，摇臂轴有切边的面应朝缸头
盖顶部，有油孔的一侧朝底部。注意进、
排气不要错装。
During mounting of rocker arm
shafts, the trimmed side of rocker
arm shaft shall face the top of
cylinder head cover, and the side
with oil hole shall face the bottom.
Pay attention to not misplacing the
intake and exhaust rocker arm
shafts.
2. 缸头盖部装好后，转动摇臂，摇臂应转动
灵活，无卡滞现象，
After assembling of cylinder head
cover, rotate the rocker arms, which
shall rotate flexibly and be free of
clamping.
3. 小盘螺栓 M6×18 紧固力矩：8~10N·M
Tightening torque of small M6×18
pan-head bolts: 8~10N·M
4. 摇臂轴定位板螺栓紧固扭矩：8～16N·m。
Tightening torque of rocker arm shaft
locating plate bolt: 8～16N·m
油孔
Oil hole
油孔
Oil hole
进气侧
Intake
side
排气侧
Exhaust
side

共50 页第15 页
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汽缸头的安装
Installation of Cylinder Head
1、装上新汽缸头密封垫，再装上 2颗圆柱销
φ6×12。
Mount the new cylinder head sealing
gasket, and then mount 2 cylindrical pins
(φ6×12).
2、将缸头装到 A、B栓上。
Mount the cylinder head on AB bolts.
3、在右图所指位置打硅胶。
Apply silica gel at the position indicated in
the picture on the right.
4、再将垫圈放到 A、B栓上，然后将 ZS500A、
B栓螺母装到 A、B拴上并紧固。
Put washers on AB bolts, and then mount
ZS500 nuts on AB bolts and tighten them.
注意：
Note:
1. 不能让尘土和渣滓进入汽缸内；
Prevent dust and dross from entering
the cylinder.
2. A、B栓螺母紧固扭矩：40～45N.m。
Tightening torque of AB bolts: 40～
45N.m
5、将凸轮轴装到缸头上，再将正时链条装到凸
轮轴上的正时从动链轮上，再安装轴承档
板、轴承 6201，然后检查发动机是否处在
正时位置，若不在正时位置需重新调整发动
机的正时位置。
Mount camshaft onto cylinder head, and
timing chain onto timing driven sprocket of
camshaft; install bearing baffle and bearing
6201, and then check whether the engine
is in the timing position; if not, the timing
position of engine shall be readjusted.
注意轴承档板的安装方向
Pay attention to installation
direction of bearing baffle.
轴承 6201
Bearing 6201
凸轮轴
Camshaft
圆柱销 φ6×12
φ6×12 cylindrical
pin
排气火花塞侧 AB 栓打硅胶
A
pply silica gel on AB bolt
on the exhaust ignition
plug side.

共50 页第16 页
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CBS300 发动机正时调整的方法：
Method for timing adjustment of CBS300
engine:
(1) 拆下左前盖的大视孔盖及小视孔盖；
Remove the large and small hole
caps of the left front cover.
(2) 用14#套筒旋转磁电机锁紧螺栓，同时通
过小视孔观察磁电机转子上的正时刻度
线“∣”（非电喷状态带“T”标识）与左前
盖上的正时标记是否对正；
Rotate the lock bolt of magnetor with
the #14 socket, and observe through
the small hole whether the timing
scale mark “∣” (marked with “T” in
the status other than electronic
injection) on the magnetor rotor is
aligned with the timing mark on the
left front cover.
(3) 上述正时标记对正后注意观察正时从动
链轮上的正时标记是否与合盖面在同一
平面上；
After alignment of above-mentioned
timing marks, pay attention to
observing whether the timing mark
on timing driven sprocket and the
cover closing face are on the same
plane.
只有同时满足（2）（3）发动机才处于正确的
正时位置。
The engine is in the correct timing
position only when items (2) and (3) are
satisfied simultaneously.
6、调整好正时位置后将大视孔盖和小视孔盖
装配到左前盖上。
Mount the large and small hole caps onto
the left front cover after adjusting the
timing position.
7、将张紧器装到缸体上对应的孔中，并用 2颗
GB70.1 内六角螺栓 M6×16 紧固，最后将张
紧器张紧，装配张紧器密封螺栓 M6×6。
Mount the tensioner in the corresponding
hole on the cylinder body and fasten it with
2 pieces of GB70.1 M6×16 hexagon
socket head bolts; then stress the
tensioner and mount the tensioner sealing
bolt (M6×6).
同时对正
Simultaneously
ali
g
ned
注意：点在右侧
A
ttention: The
point is on the
right side.

共50 页第17 页
Page 17 of 50
注意
Note
安装张紧器前，先用薄片顺时针旋转螺杆将发
条弹簧收回。2颗紧固螺栓安装好后，取出薄
片，使弹簧弹出，张紧器处于张紧状态。
Before installing the tensioner, rotate the
bolt clockwise with a slice to retract the
clockwork spring; after mounting 2
fastening bolts, take out the slice to pop
up the spring and make the tensioner in
the tensioning state.
8、将NC250 凸轮轴挡板装到缸头的挡板槽中，
最后将 NC250 缸头密封胶套装到缸头的密
封胶套槽中。
Mount the NC250 camshaft position plate
in the position plate groove on the cylinder
head, and then mount the NC250 cylinder
head sealing bush in the sealing bush
groove of cylinder head.
气缸头盖的安装
Installation of Cylinder Head Cover
1、将气缸头盖与缸头结合面清理干净，在气缸
头盖接合面均匀涂抹一层硅橡胶平面密封
剂；
Clean up the jointing faces of cylinder head
cover and cylinder head, and apply a layer
of silicon rubber as the planar sealant on
the jointing face of cylinder head cover.
2、将缸头盖装到缸头上；
Mount cylinder head cover onto cylinder
head.
3、将2颗GB/T16674 小盘螺栓 M6×105、2
颗GB/T16674 小盘螺栓 M6×20 、1颗
GB/T16674 小盘螺栓 M6×32 、1颗
GB/T16674 小盘螺栓 M6×28、2颗GB5789
大盘螺栓 M6×65、2颗铜垫片 φ6.2×2×φ13
装配到位并紧固。
Mount in place 2 small GB/T16674
M6×105 pan-head bolts, 2 small
GB/T16674 M6×20 pan-head bolts, 1
small GB/T16674 M6×32 pan-head bolt, 1
small GB/T16674 M6×28 pan-head bolt, 2
large GB5789 M6×65 pan-head bolts and
2 copper gaskets (φ6.2×2×φ13), and
tighten them.
注意
Note
紧固扭矩：11～13N·m
Tightening torque: 11～13N·m
油孔附近胶量不能过
多，否则会堵塞油孔。
A
mount of silica gel
around oil hole shall
not be excessive,
otherwise the oil hole
will be clogged.

共50 页第18 页
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4、调节进、排气门的间隙，气门的间隙值：
0.02～0.04mm。
Adjust the clearance of intake and exhaust
valves; clearance value of valves: 0.02～
0.04mm
5、将气门室盖装到缸头盖上并用 GB/T16674
小盘螺栓 M6×20 紧固，紧固扭矩：11 ～
13N.m。
Mount the valve chamber covers onto the
cylinder head cover and tighten them with
small GB/T16674 M6×20 pan-head bolts;
tightening torque: 11～13N.m
6、将启动电机安装到左盖对应的孔内，用 2颗
GB5789 大盘螺栓 M6×28 紧固，注意不要
遗漏 1颗电机安装座圈。
Mount the starting motor in the
corresponding hole of left cover and fasten
it with 2 large GB5789 M6×28 pan-head
bolts; pay attention to not omitting 1 motor
mounting seat ring.

共50 页第19 页
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汽缸及活塞
Cylinder and Piston
维修须知
Maintenance instructions
故障排除
Troubleshooting
汽缸的拆卸
Removal of cylinder
气门的检查
Inspection of valves
活塞的拆卸
Removal of piston
活塞、活塞环的检查
Inspection of piston and piston ring
活塞环的安装
Installation of piston ring
活塞的安装
Installation of piston
气缸体的安装
Installation of cylinder body
维修须知
Maintenance Instructions
总则
General
注意事项：
Notes:
● 缸头润滑油是经由发动机右体 AB 栓旁边的油孔到汽缸头的，在安装汽缸之前，应确保右体
AB 栓旁边的油孔畅通。
Cylinder head lubricating oil is supplied to the cylinder head through the oil hole beside the
AB bolt on the right engine body; before cylinder installation, make sure the oil hole beside
AB bolt of right body is unblocked.
● 不能使灰尘或尘埃渗入曲轴箱内。
Prevent dust or dirt from entering the crankcase.
各部规格
Parameters of Components
项目
Item
标准值 mm
Standard Value
(mm)
维修极限值 mm
Maintenance Limit
Value (mm)
汽缸
Cylinder
汽缸内径
Inner diameter of cylinder φ74～φ74.01 φ74.018
圆度
Roundness 0.004 0.008
缸面平面度
Planeness of cylinder face 0.03 0.06
活塞
活塞环活
塞销
活塞外径
Outer diameter of piston φ73.96～φ73.97 φ73.94
活塞销孔内径
Inner diameter of piston pin hole φ16.001～φ16.006 φ16.015

共50 页第20 页
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项目
Item
标准值 mm
Standard Value
(mm)
维修极限值 mm
Maintenance Limit
Value (mm)
Piston,
Piston Ring
and Piston
Pin
活塞环闭合间隙
Closure clearance of
piston ring
顶环/第二环
Top
ring/second
ring
0.2～0.35 0.5
油环
Oil ring 0.2～0.7 1.4
活塞环与活塞环槽间
隙
Clearance between
piston ring and
piston ring groove
顶环
Top ring 0.03～0.07 0.08
第二环
Second ring 0.02～0.06 0.08
汽缸与活塞间隙
Clearance between cylinder and
piston
0.035～0.045 0.07
活塞销外径
Outer diameter of piston pin φ15.994～φ16 φ15.99
活塞销与活塞销孔间隙
Clearance between piston pin and
piston pin hole
0.001～0.012 0.025
连杆小端
Small End
of
Connecting
Rod
内径
Inner diameter φ16.015～φ16.025 φ16.04
连杆小端与活塞销间隙
Clearance between small end of
connecting rod and piston pin
0.015～0.03 0.05