Suzuki: Engine K6A-YH6. Manual - part 9

THEORY OF OPERATION

4-13

4

4.7 Cylinder Block and Lower 
Crankcase

See Figure 4-14.

Figure 4-14

The cylinder block (1) is made of a lightweight aluminum 
alloy. The cylinders contain press-fit, semi-wet style liners 
for improved cooling and reliability.

The lower crankcase (2) is made of lightweight aluminum 
alloy. The journal bearing caps are integrated into the 
casting, which makes it possible to reduce weight, 
improve rigidity, and suppress vibrating noise.

Crankshaft

See Figure 4-15.

Figure 4-15

The crankshaft (1) is constructed of cast iron. The 
crankshaft has four main bearing journals and three rod 
bearing journals, and is counterbalanced on rod throws 1 
and 3 to reduce vibration. Each main journal contains a 
two-piece main bearing (4 and 5), which is lubricated via 
an oil hole (3). The third main journal contains a thrust 
bearing (2). The front-mounted timing sprocket drives 
both the timing chain and oil pump inner rotor. The 
crankshaft pulley is equipped with a damper to reduce 
vibration.

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4-14

THEORY OF OPERATION

4

Connecting Rod

See Figure 4-16.

Figure 4-16

The connecting rod is made of carbon steel with an 
H-shaped cross section. The rod consists of two pieces, 
the main beam (1) and the rod cap (3), which is fastened 
with special reamer type rod bolts and nuts. The small 
end of the rod is machined for a full-floating piston pin. An 
oil jet (2) lubricates the cylinder wall, piston, and piston 
pin. The rod bearings (4) are made of an aluminum alloy.

Piston, Piston Rings, and Piston Pin

See Figures 4-17 and 4-18.

Figure 4-17

Figure 4-18

The three-ring, skirt-type, full-floating pistons (1) are 
made of an aluminum alloy. The pistons are equipped 
with intake valve reliefs (2) machined into the face. The 
piston pin bores are equipped with “Ricardo Grooves” (3) 
to aid in lubrication. The piston is assembled in the 
engine with the floating-fit piston pin for lower friction.

All piston rings are located above the piston pin. The two 
top rings are compression rings and the 3rd (6) is an oil 
ring.

The 1st ring (4) is of barrel face type designed for 
improved initial breaking in. The 2nd ring (5) is of taper 
undercut type designed for better oil scraping 
performance. A hard chrome is plated on the 
circumference of the 1st ring for extended durability.

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5-2

TESTS AND ADJUSTMENTS

5

5.1 Air Intake and Exhaust 
Systems

Intake Manifold Vacuum Test

See Figure 5-1.

1.

Warm up the engine.

Figure 5-1

2.

Stop the engine.

3.

Remove hose (2) from PCV valve and install vacuum 
gauge (1) to PCV hose (2).

NOTES

Cap or plug PCV valve.

Place transmission in neutral position.

4.

Start the engine. Measure the intake manifold 
vacuum at idle.

Intake Manifold Vacuum at Idle: At least 7.7 psi (53 
kPa)

5.

Stop the engine. Remove the vacuum gauge and 
install the PCV hose.

PCV Valve/Hose Test

See Figures 5-2 and 5-3.

Figure 5-2

1.

Remove the PCV valve (1) from the cylinder head 
cover.

2.

Start engine and bring to idle. Block the end opening 
of PCV valve. Suction (vacuum) should be detected.

3.

If any abnormal condition is found, replace the PCV 
valve and hose.

Figure 5-3

4.

Remove the PCV valve and verify the internal check 
ball can be heard when shaking the valve.

5.

If any abnormal condition or restriction is found, 
replace the PCV valve and hose.

Required Tools

Vacuum Gauge: Suzuki PN 09915-67311 or 
Equivalent

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TESTS AND ADJUSTMENTS

5-3

5

5.2 Cooling System

Thermostat Test

See Figures 5-4 and 5-5.

Figure 5-4

1.

Check that the air bleed valve (1) of thermostat is not 
blocked.

2.

Inspect valve seat (2) for any substance that could 
interfere with sealing.

Figure 5-5

3.

Immerse the thermostat (4) in water and heat it 
gradually with an appropriate heater (5).

4.

Observe thermometer (3) to verify that the 
thermostat opens at the specified temperature. 
Replace thermostat if not to specifications.

Thermostat Start-to-Open Temperature:
190°F (88°C)

Full Open Temperature: 205°F (96°C)

5.3 Cylinder Head, Cams, and 
Valve Train

Valve Clearance Check and 
Adjustment

See Figures 5-6 through 5-13.

Check

Figure 5-6

1.

Remove the cam cover (1). (See “Cam Cover” on 
page 7-17.)

Figure 5-7

2.

Turn the crankshaft clockwise as viewed from front.

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Valve 

Clearance

Intake

Exhaust

Cold

0.007—0.009 in.
(0.18—0.23 mm)

0.012—0.014 in.
(0.30—0.35 mm)

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