Haima M3. Service Manual - part 3

 

Engine block 1A-28 

 

Valve Mechanism Dismantling/ Mounting 

1.  Dismantle cylinder head(see the cylinder head 

dismantling).  

2.  Dismantle parts according to sequence 

illustrated in the figure. .   

3.  Mount the parts according to the sequence 

reverse to the dismantling process.   

 

 

   

1 

Valve Half (see dismantling/mounting 
explanations) 

2 

Valve spring upper seat   

3 

Valve spring (see the mounting 
explanations) 

4 

Valve spring lower seat   

5 

Valve (see the mounting explanations)

6 Valve 

oil 

seal 

 

Explanations on inspection of valve 
clearance 

1.  Dismantle the cylinder head hood (see 

cylinder head hood dismantling part).   

2.  Confirm if the engine has been cooled.   

3.  Measure valve clearance.   

(1)  Rotate the crankshaft along the clockwise 

direction, making the piston located at the 
stopping place on No.1 Cylinder, namely, gas 
distribution mark shall be adjusted to the 
position indicated in the right figure.   

(2)  Use plug gauge to measure valve clearances 

of all cylinders at Mark A indicated in the 
figure.  

 

★

  Note:If the valve clearance exceeds the 

standard value, replace the tappet(see the 
valve clearance’s adjustment)valve 
clearance’s standard value (when engine is in 
cooling state): 
Intake:0.18～0.26mm 
Exhaust:0.26～0.34mm 

(3)  Rotate the crankshaft for 360 degrees along 

the clockwise direction, making the piston 
located at the stopping place on No.4 
Cylinder, namely, gas distribution mark shall 
be adjusted to the position indicated in the 
figure below.   

 

(4)  Use plug gauge to measure valve clearances 

of all cylinders at Mark B indicated in the 
figure above.   

★

  Note:If the clearance exceeds standard value, 

tappet shall be replaced(see the valve 
clearance’s adjustment) 

Valve clearance’s standard value (when the engine 
is in cooling state): 

ON:0.18～0.26mm 

OFF:0.26～0.34mm 

4.  Mount cylinder head hood (see the timing 

chain, cylinder head hood mounting part).   

 

Engine block 1A-29 

 

Explanations on the valve clearance’s 
adjustment  

To adjust the valve clearance, operation steps 
below shall be observed: 

1.  Dismantle camshaft (see the camshaft 

dismantling part).   

2.  Take out the tappet at the place where the 

valve clearance shall be adjusted.   

3.  Select an apposite tappet. New tappet’s 

thickness =old tappet’s thickness + measured 
valve clearance － standard valve clearance. 
(standard valve clearance: ON, 0.22mm; OFF, 
0.30mm) 

4.  Mount the selected tappet into the tappet hole.   

5.  Confirm the valve clearance again (see valve 

clearance, valve clearance inspection).   

 

Notice: 

  If the valve clearance will be adjusted when 

there is not timing chain, make the crankshaft 
dowel pin towards side face, in order to 
prevent the valve from colliding with the 
piston top during the valve clearance 
adjustment process.   

  Mark the tappet thickness inside the tapper 

with 3 digits, see figure below:   

 

 

Cylinder Head Inspection /Repair   

1.  Inspect the cylinder head’s defect. If 

necessary, replace the cylinder head.   

2.  Inspect the following items, repair and 

replacement shall be conducted if necessary.   

(1).  If there is indentation at the valve seat.   

(2).  If the camshaft journal clearance and end gap 

is excessive.   

3.  Use the Straight Edge Ruler and plug gauge 

to inspect if the cylinder head is distorted 
along six directions, see the figure.   

Maximum distortion: 0.06mm 

 

 

 

4.  If the cylinder head’s distortion exceeds the 

maximum value, inspect the cylinder head’s 
height. If the height stays beyond the standard 
value, replace the cylinder head.   

Standard height:112.9-113.1mm 

Valve spring ejector

Pivot

 

Thickness mark

 

Engine block 1A-30 

 

5.  If the cylinder head’s distortion exceeds the 

maximum value, and the height stays within 
the standard value, grind the height or replace 
the cylinder head.   

Maximum grinding volume:0.20mm 

6.  Use the Straight Edge Ruler and plug gauge 

to measure the cylinder head intake/ exhaust 
manifold flange’s distortions along different 
directions, see the figure.   

Maximum distortion: 0.05mm 

 

 

 

7.  If the distortion measured in Step 6 exceeds 

the maximum value, grind the surface or 
replace the cylinder head.   

Maximum grinding volume: 0.20mm 

Inspection of Valve and Valve Guide 

1.  Measure thickness of every valve’s head rim. 

If necessary, replace the valve. 

Standard thickness: intake valve: 1.35mm; exhaust 
valve: 1.85mm.   

Minimum thickness: intake valve: 0.85mm; 
exhaust valve: 1.35mm.   

 

 

 

 

2.  Measure every valve’s length. If necessary, 

replace the valve.   

Standard length   

Intake valve:89.31～89.91mm 

Exhaust valve:90.63～91.23mm 

Minimum length   

Intake valve: 89.11mm 

Exhaust valve: 90.43mm 

 

3. Measure every valve’s rod diameter 

respectively at A, B, C point (see the figure) 
along X and Y direction. If necessary, replace 
the valve.   

Standard diameter 

Intake valve: 4.965～4.980mm 

Exhaust valve: 4.955～4.970mm 

Minimum diameter 

Intake valve: 4.915mm 

Exhaust valve: 4.905mm 

4.  Measure every valve guide’s inner diameter 

respectively at A, B, and C point along X and 

Brim th

ic

knes

s

 

Engine block 1A-31 

 

Y direction (see the figure). If necessary, 
replace the valve guide.   

Standard inner diameter 

Standard:5.0～5.012mm 

 

5.  When there is not valve spring’s lower seat, 

measure every valve guide’s extrusion height 
(Size A). If necessary, replace the valve 
guide.  

Standard height:12.7～13.3mm 

   

Explanations on inspection of valve 
spring 

1.  Use the special tools to exert pressure on the 

valve spring, and inspect the spring height. If 
necessary, replace the valve spring. Exert 
pressure on the valve spring, and compress 
the spring to a given height, when the 
pressure value exceeds the specified range, 
the valve spring shall be replaced.   

When the height is 33.4mm, the pressure is 142.2～
161.8N{14.51～16.51kgf}; 

When the height is 24.9mm, the pressure is 
293.4～324.4N{29.94～33.10kgf}.  

2.  Measure the valve spring verticality, and if 

the verticality goes beyond the standard, the 

valve spring shall be replaced.   

Valve spring’s maximum verticality:1.50mm 

 

Explanations on the inspection of 
camshaft 

1.  Place the camshaft’s No. 1 and No. 5 journals 

onto the V-shaped block to measure the 
camshaft’s radial run-out. If necessary, 
replace the camshaft.   

Radial run-out: 0.03mm 

 

 

2.  Measure heights of the two convex parts (see 

the figure). If necessary, replace the camshaft.   

Standard height   

Intake side: 44.71mm 

Exhaust side: 44.28mm 

Minimum height   

Intake side: 44.51mm 

Exhaust side: 44.08mm 

Valve guide

Cylinder head 

 

Engine block 1A-32 

 

 

3.  Measure the journal diameter respectively at 

A and B point along X and Y direction. If 
necessary, replace the camshaft.   

Standard diameter:25.940～25.965mm 

Minimum diameter: 25.910mm 

 

4.  Dismantle the tappet, and measure camshaft 

journal clearance according to steps below: 

(1). Remove all oil on the journal and bearing 

seat’s internal surface.   

(2).  Put the camshaft into the bearing seat.   

(3). Make the plastic gauge match the bearing 

width (see the figure), and then put it on the 
top of journal along the axial direction.   

(4).  Mount the camshaft cover (see cylinder head 

dismantling/mounting, camshaft mounting 
attentions).  

 

Notice 

  When measuring the clearance, do not rotate 

the camshaft 

(5).  Dismantle camshaft cover (see cylinder head 

dismantling/mounting, camshaft dismantling 
attentions).  

(6). Use the scale on the plastic gauge bag to 

measure the widest point on the plastic 
gauge’s extruded part, and then calculate out 
the journal clearance.   

If necessary, replace the cylinder head and 
camshaft cover.   

Standard journal clearance:0.040～0.076mm 

 

5.  Mount the camshaft cover (see cylinder head 

dismantling/mounting, camshaft mounting 
attentions).  

6.  Mount the dial gauge, push camshaft forward 

or backward at the end of camshaft (see the 
figure), and measure the camshaft end gap. If 
necessary, replace the cylinder head or 
camshaft.  

Caution 

  Do not push the camshaft at the cam part, so 

as to prevent the cam from being damaged.     

Standard end gap:0.08～0.20mm 

Maximum end gap:0.21mm 

 

Point A 

Point B 

Axial direction 

Plastic gauge 

 

Engine block 1A-33 

 

Explanations on inspection of tappet hole 
and tappet 

1.  Measure every tappet mounting hole’s inner 

diameter respectively at A and B Point (see 
the figure) along X and Y direction.   

Standard inner diameter:31.000～31.025mm 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.  Measure every tappet’s diameter respectively 

at the A and B point (see the figure) along X 
and Y direction.   

Standard diameter:30.964～30.980mm 

 

3.  Calculate the clearance between tappet and 

corresponding tappet hole. If necessary, replace 
the tappet or cylinder head.   

Standard clearance:0.020～0.061mm 

Maximum clearance:0.180mm 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Engine block 1A-34 

 

Flywheel, clutch 

 

Flywheel and Clutch Dismantling/Mounting 

1.  If the crankshaft’s back cover needs to be dismantled, oil sump body shall be dismantled at first (see 

lubricating system, oil sump body dismantling and mounting).   

2.  Dismantle parts according to sequence illustrated in the figure. .   

3.  Mount the parts according to the sequence reverse to the dismantling process.   

 

 

 

 

1 

clutch pressure plate  (see dismantling explanations/see mounting explanations) 

2 

Clutch friction disc (see dismantling explanations/see mounting explanations) 

3 

flywheel 

(see dismantling explanations/see mounting explanations) 

4 

Crankshaft’s back cover 

(see the rear oil seal dismantling explanations /see rear oil seal 

mounting explanations /see mounting explanations) 

5 Transmission’s 

baffle 

plate 

 

 

 

 

 

 

 

Engine block 1A-35 

 

Explanations on Clutch Pressure 
Plate/Friction Disc Dismantling   

1.  Use the special tools to lock the flywheel, and 

locate the clutch(see the figure).   

2.  Loosen the bolt in a disposable manner 

according to the sequence of right-angled 
intersection till the diaphragm spring’s 
pressure is released.   

3.  Dismantle the clutch pressure plate and 

friction disc.   

 

Explanations on flywheel dismantling   

1.  Use the special tools (see the figure) to lock 

the flywheel.   

2.  Follow the right-angled intersection sequence 

to evenly dismantle the mounting bolt (see the 
figure), and dismantle the flywheel.   

 

Explanations on Rear Oil Seal 
Dismantling/Mounting 

1.  Use the screwdriver, wrapped with protective 

cloth, to dismantle the oil seal(see the figure) 

Notice 

  Normally, there is no need to dismantle the oil 

seal, unless being replaced.     

2.  Add clean oil onto the oil seal opening.   

3.  Mount the oil seal with hands.   

4.  Use the special tools and hammer to compress 

the oil seal.   

Compression depth:0～0.5mm 

 

 

 

Explanations on the crankshaft’s back 
cover mounting   

1.  Smear evenly sealant onto indentation of the 

crankshaft’s back cover (see the figure). 

Sealant diameter:Φ1.5～Φ2.5mm 

 

Explanations on the flywheel mounting 
/inspection  

1.  Mount the flywheel onto the crankshaft.   

2.  Clean the thread and hole before mounting the 

bolt.  

3.  Smear evenly the sealant onto the thread.   

Notice 

  There is no need to smear the sealant when 

using new bolt 

4.  Tighten the flywheel bolt with hands.   

5.  Mount special tools onto the flywheel (see the 

figure).  

6. Follow the sequence of right-angled 

intersection to tighten the flywheel bolt little 
by little.   

 

Protective 
cloth 

Smear sealant 

Clutch plate setting tool 

Gear ring fixture unit

Gear ring fixture unit

Gear ring fixture 
unit 

 

Engine block 1A-36 

 

7.  Mount the dial gauge onto the cylinder body.   

8.  Rotate the flywheel and measure the 

flywheel’s end-on circle run-out. If it exceeds 
the standard, replace the flywheel.   

Maximum end-on circle run-out:0.13mm 

 

Explanations on the clutch friction disc 
inspection /mounting   

Use the vernier caliper to measure rivets on both 
sides and the friction disc surface’s depth.   

If it exceeds the standard, replace the clutch 
friction disc 

Minimum depth:0.3mm 

 

Use the dial gauge to measure the clutch friction 
disc’s end-on circle run-out.   

If it exceeds standard, replace the clutch 
friction disc 

Maximum end-on circle run-out:0.7mm 

 

Use the special tools to secure the clutch friction 
disc’s position (see the figure).   

 

 

Explanations on the clutch pressure plate 
inspection/mounting 

1.  Measure the diaphragm spring’s abrasion.   

If it exceeds standard, replace the clutch 
pressure plate 

Maximum height: 0.6mm 

 

2.  Use the Straight Edge Ruler and plug gauge 

to measure the pressure plate’s flatness.   

If it exceeds standard, replace the clutch 
assembly.  

Maximum clearance: 0.05mm 

 

3.  Use the special tools to lock the flywheel, and 

locate the clutch(see the figure).   

 

Clutch plate 
locator 

 

Engine block 1A-37 

 

 

 

4.  Follow the right-angled intersection sequence 

to evenly tighten bolts.   

5.  Mount the dial gauge onto the cylinder body, 

and rotate the flywheel to inspect the 
diaphragm spring’s radial run-out.   

If it exceeds standard, replace the clutch 
pressure plate 

Maximum radial circle run-out:0.6mm 

 

Cylinder body, Crank Connecting 
Rod Mechanism   

Cylinder Body, Crank Connecting Rod 
Mechanism Dismantling/Mounting 

1.  Dismantle the cylinder head (see the cylinder 

head part), oil sump, oil pump, and timing 
chain case assembly (see lubricating system 
part) and crankshaft’s back cover (see 
flywheel, clutch part).   

2.  Dismantle parts according to sequence 

illustrated in the figure. .   

3.  Mount parts according to the sequence 

reverse to the dismantling process.     

 

 

 

 

1 

connecting rod 
cover (see the 
mounting 
explanations) 

7 

Main bearing cover 
(see the mounting 
explanations) 

2 

connecting rod 
bearing  

8 thrust 

bearing 

3 

piston ring(see the 
mounting 
explanations) 

9 Crankshaft 

bearing 

4 

Piston pin (see the 
mounting 
explanations) 

10 Crankshaft 

5 piston 

11  Cylinder body   

6 connecting 

rod 

   

Explanations on connecting rod cover 
dismantling  

Inspect the connecting rod end gap (see connecting 
rod inspection part).   

Explanations on piston pin dismantling   

1.  Mount No. 1 and No. 2 special tools and 

insert the No. 2 special tool into piston pin 
and tighten it (see the figure)   

Clutch plate setting tool 

Gear ring fixture unit

Smear oil 
before 
mounting 

⑨

Smear oil 

before 
mounting 

②

Smear oil 

before mounting

 

Engine block 1A-38 

 

 

 

2.  Mount the special tools and piston connecting 

rod assembly, which have been assembled in 
Step 2, onto the special tools (see the figure).   

 

3.  Use the press machine to extrude the piston 

pin.  

Explanations on main bearing cover 
dismantling  

1.  Inspect the crankshaft end gap (see the 

crankshaft inspection /repair part).   

2.  Loosen the main bearing cover’s bolt 

according to steps illustrated in the figure.   

 

 
 

 

Explanations on the crankshaft 
dismantling  

Inspect the main journal clearance (see the 
crankshaft inspection /repair part).   

Explanations on the main bearing cover 
mounting  

1.  Measure every bolt’s length. If the length 

exceeds the standard value, replace the bolt.   

Standard length: 74.15～74.85mm 

Maximum length: 75.05mm 

 

2.  Tighten main bearing cover’s bolt to specified 

torque by steps according to the sequence 
illustrated in the figure, as well as mark every 
bolt head. Tightening torque:33 ～
35N·m{3.357～3.784kgf·m} 

3.  according to the bolt-tightening sequence 

(Step 2) illustrated in the figure, rotate every 
bolt for 60°～64° from the mark.   

 

Piston F’s mark side

Piston F’s mark side

No. 1 tool

No. 2 tool

Piston pin 

Extrusion direction 

Catch bolt 

Piston pin assembly tool

 

Engine block 1A-39 

 

Explanations on the piston pin mounting   

1.  Use the special tools for mounting.   

2.  Measure the following sizes (see the figure): 

(1)A: exterior size of piston’s pin seat convex 
plate 

(2)B: piston cavity’s spread width   

(3)C: piston pin length   

(4)D: connecting rod’s small head width   

(5) Put measured values into the formula 
below: 

 

 

3.  Insert the No. 2 special tool into the piston pin 

and tighten it onto the No. 1 special tool.   

4.  Measure length of No. 2 special tool’s 

guiding part (L2), and adjust it to compress 
the special tool (catch bolt), so as to make the 
L’s size equal to L2＋h.  

 

5.  Smear the clean engine oil onto the piston pin.   
 
 
 
 
 
 

 

 

6.  Place the piston and connecting rod onto the 

compression platform, and keep upward the 
piston “F” mark side and connecting 
rod“HM15A” or “474Q-C” mark side (see the 
figure).  

   

7.  Insert the piston pin and the special tool that 

has been assembled in Step 2 into the piston 
and connecting rod (see the figure).   

8.  Use the press machine to press the piston pin 

into the piston and connecting rod till No. 2 
special tool (guide) contact the special 
tool(catch bolt).   

9.  When pressing the piston pin, inspect the 

compression pressure. If the pressure is 
lower than the index, replace the piston 
pin or connecting rod.   

Pressure:5～11kN(510～1122kgf) 

 

10.  Inspect the piston pin’s compression depth, if 

it goes beyond the standard value, repeat the 
operation from step 1.   

Piston pin’s compression depth:0.350～1.375mm 

h= 

B

CAD 

2 

Piston pin 
assembly tool

Piston pin 
assembly tool

Catch bolt

Piston F’s mark side

Connecting rod“HM15” mark side

Piston 

Piston pin 

Connecting rod 

No. 1 tool 

No. 2 tool 

Connecting rod 

“F” mark side 

 

Engine block 1A-40 

 

   

Explanations on the piston ring mounting   

1.  Mount the corrugated ring into the piston ring 

slot, and then mount one end of the oil scraper 
into the slot with hands. After that, compress 
other parts (see the figure). After the 
mounting, inspect if all pieces can move 
smoothly along two directions.   

Caution 

  Do not use the piston ring dilator to mount the 

oil scraper, or rupture may be caused.   

 

2.  Use the piston ring dilator to mount the No. 2 

and No.1 piston ring. Keep the marker side 
upward during the mounting process.   

3.  Align all rings’ opening locations (see the 

figure).  

 

 

Explanations on piston connecting rod 
assembly mounting   

1.  Keep the piston “F” marker side face towards 

the engine’s frontal part;   

2.  When mounting the connecting rod cover, 

align the connecting rod cover’s location 
marker.  

 

Explanations on the connecting rod cover 
mounting  

1.  The bolt can be reused, but when the outer 

diameter difference at the two points 
illustrated below exceeds 0.1mm, the bolt 
shall not be further used.   

 

2.  Tigthen the connecting rod bolt to specified 

torque by steps according to the sequence 
illustrated in the figure.   

Tightening torque:13.0 ～ 17.0N·m{1.32 ～
1.74kgf·m} 

Piston pin’s 
depth in the 
convex plate 

No. 1 
gas ring

Possible locations of all 
piston rings’ abutment joints

Upper 
scraper

 

Thrusting 
direction

 

Lower 
scraper

 

No. 2 gas 
ring 

Piston pin direction

 

Piston ring dilator 

Outer 

diam

eter  

Outer 

diam

eter  

 

Engine block 1A-41 

 

 

3.  Mark every bolt head.   

4.  According to the bolt-tightening sequence 

(Step 2) illustrated in the figure, rotate every 
bolt for 90°～94° from its marker.   

Cylinder Body Inspection /Repair   

1.  Use the Straight Edge Ruler and plug gauge 

to measure the distortion on the cylinder 
body’s upper surface along six directions 
illustrated in the figure.   

Cylinder body’s maximum distortion:0.1mm 

 

2.  If the distortion on the cylinder body’s upper 

surface exceeds the maximum value, inspect 
the cylinder body’s height. If the height stays 
beyond the standard value, replace the 
cylinder body.   

 

Cylinder body 

Standard height:204.95～205.05mm 

3.  If the cylinder body’s distortion goes beyond 

the maximum value and the height stays 
within the standard value, grind the height or 
replace the cylinder body.   

 

Maximum grinding volume: 0.20mm 

4.  Use the inside dial indicator to measure the 

cylinder’s inner diameter at the place 60mm 
away from upper surface along the X and Y 
direction (see the figure).     

 

5.  If the cylinder’s inner diameter goes beyond 

the abrasion limit, replace the cylinder body, 
and install the corresponding piston, in order 
to make it accord with the standard clearance 
between piston and cylinder. Abrasion limit: 
0.135mm 

Piston, Piston Ring, and Piston Pin 
Inspection  

Along the vertical direction of piston pin hole’s 
axial line, measure the piston’s diameter at the 
place that is 19.38mm below the lower rim of the 
oil control ring groove   

 

    In 

Front 

Row 

Cylinder body’s upper surface 

 

Engine block 1A-42 

 

 

 

Piston diameter 

   (mm) 

Size Diameter 

Standard 74.78～74.79 

Calculate the clearance between piston and 
cylinder. If necessary, replace the piston.   

Standard clearance:0.010～0.035mm 

Maximum clearance: 0.10mm 

1.  If replacing the piston, piston ring shall be 

replaced as well.   

2.  Use the plug gauge to measure the clearance 

between piston ring and ring slot along the 
entire perimeter (see the figure). If necessary, 
replace the piston and piston ring.   

 

Standard clearance 

Ring 1:0.030～0.070mm 

Ring 2:0.020～0.060mm 

Oil ring:0.040～0.12mm 

Maximum clearance   

Ring 1, Ring2:0.15mm 

Oil ring:0.15mm.   

3.  Put the piston ring into cylinder with hands, 

and use the piston to push the piston ring to 
the bottom of the cylinder bore stroke.   

4.  Use the plug gauge to measure every piston 

ring’s opening clearance. If necessary, replace 
the piston ring.   

Standard opening clearance: 

Ring 1:0.15～0.30mm 

Ring 2:0.20～0.40mm 

Oil Ring:0.10～0.40mm 

Maximum opening clearance:1.0mm 

 

 

Respectively at A, B, C, and D point along X and 
Y direction, measure every piston pin hole’s 
diameter.  

Standard diameter:18.010～18.014mm 

Respectively at A, B, C, and D point along X and 
Y direction, measure every piston pin’s diameter 

Standard diameter:18.001～18.005mm; Calculate 
out the clearance between piston pin and piston pin 
hole. If necessary, replace the piston or piston pin.   

Standard clearance:0.005～0.013mm 

5.  Measure the connecting rod’s small head 

diameter (see connecting rod inspection), and 
calculate the clearance between connecting 
rod’s small head and piston pin. If necessary, 
replace the connecting rod or piston pin. 
Standard clearance:-0.031～-0.016mm. 

Connecting Rod Inspection   

1.  Use the plug gauge to measure the connecting 

 

Engine block 1A-43 

 

rod’s end gap. If necessary, replace the 
connecting rod and connecting rod cover.   

 

Standard clearance:0.100～0.350mm 

Maximum clearance:0.40mm 

2.  Measure the crank pin journal clearance 

according to steps below.   

(1). Remove all oil on the journal and bearing 

seat’s internal surface. 

(2). Make the plastic gauge match the bearing 

width and then put it on the top of journal, 
keeping parallel with the axial line.   

(3).  Mount the connecting rod cover (see piston 

and connecting rod mounting part).   

(4). Dismantle the connecting rod cover’s bolt, 

and slowly take off the connecting rod cover.   

(5). Use the plastic gauge scale to measure the 

widest point on the plastic gauge’s extruded 
part, and then calculate out the journal 
clearance. If the clearance exceeds the 
maximum value, replace the crankshaft and 
corresponding connecting rod bearing to 
ensure the standard clearance.   

Standard clearance:0.014～0.058mm 

 

Maximum clearance:0.10mm 

Size of connecting 

rod bearing 

Thickness of connecting 

rod bearing 

Standard 1.485～1.496 

 

Inspection of Piston Connecting Rod 
Assembly  

Inspect the swaying torque (see the figure). If the 
big head fails to drop down by virtue of its own 
weight, replace the piston or piston pin.   

 

Crankshaft Inspection /Repair   

1.  Mount the dial gauge, use the screwdriver to 

push the crankshaft frontward and backward, 
and measure the crankshaft end gap (see the 
figure). If the end gap surpasses the maximum 
value, replace the thrust bearing or crankshaft 
to fit the standard end gap.   

Standard end gap:0.09～0.273mm 
Maximum end gap:0.30mm 

Thrust bearing’s sizeThrust bearing’s thickness

Standard 3.205～3.255 

Drop down by virtue 
of its own weight