Spark Plug, Emmissions, Exhaust and Carburetor

 

SPARK PLUG

1.      Remove:
•  Spark plug(s)

2.      Inspect:
•   Electrode (1) Wear/Damage — Replace.
•  Insulator color (2)

3.      Measure:
•  Plug gap (3)

Use a Wire Gauge or Feeler Gauge. Out of specification — Regap.

0.7 ~ 0.8 mm (0.028 - 0.31 in)

Clean the plug with a spark plug cleaner if necessary-

Standard Spark Plug: BP8 ES (NGK) W24EP-U (NIPPONDENSO)

Before installing a spark plug, clean the gasket surface and plug surface. 

4. Tighten:
• Spark plug(s)

20 Nm (2.0 mkg, 14ftlb)

NOTE:
Finger-tighten the spark plug(s) before torquing to specification.

CANISTER (For California Only)

This model is equipped with a canister to prevent the discharging of fuel vapor into the atmosphere. 

1. Inspect:
•   Hoses (1) (2) (5) Cracks/Damage — Replace. Clog - Clean.
•   Canister (4) Cracks/Damage — Replace.

3 Carburetor [B] From fuel tank [C] To atmosphere

A EMISSION HOSE ROUTING

 

CRANKCASE VENTILATION SYSTEM

1. Inspect:
• Crankcase ventilation hose ® Cracks/Damage — Replace.

FUEL LINE

1. Inspect:
•  Fuel hose (1)
•  Vacuum hose (2) Cracks/Damage — Replace.

INTAKE MANIFOLD

1.     Tighten:
•  Carburetor clamps
•  Carburetor joint bolts

2.     Inspect:
•  Carburetor joint
•  Gaskets Cracks/Damage — Replace.

EXHAUST SYSTEM

1.     Inspect:
•  Exhaust pipe gasket(s) (1)
•  Muffler clamp gasket(s) (2) Damage — Replace. Exhaust gas leakage — Repair.

2.     Tighten:
•  Exhaust pipe bolts
•  Muffler bolts

Exhaust Pipe Flange (3) :
10 Nm (1.0 m-kg, 7.2ft-lb) 

Exhaust Pipe Clamp (4) :
20 Nm (2.0 m-kg, 14ftlb) 

Muffler Bracket (5) :
25 Nm (2.5 m-kg, 18 ft-lb)

Exhaust Chamber Mount (7) :
20 Nm (2.0 m-kg, 14 ft-lb) 

Muffler Clamp (6) :
20 Nm (2.0 m-kg, 1 4 ft-lb) 

IDLE SPEED/CARBURETOR SYNCHRONIZATION

IDLE SPEED

1. Adjust
• Idle speed

Warm up the engine and turn the throttle stop screw (1) to adjust.

Idle Speed

1,050 + 50 r/min

Carburetor Adjustment.

Carburetors must be adjusted to open and close simultaneously.

NOTE:
Valve clearance must be set properly before synchronizing the carburetors.

1.     Remove:
•  Seat
•  Fuel tank

2.     Disconnect:
•  Vacuum plugs (1)
•  Vacuum hose (2)

3.     Install:
•  Vacuum Gauge (YU-08030) (1)
•  Suitable test fuel tank

4.     Remove:
•  Y.I.C.S. plug (2)

5.     Attach:
•  Y.I.C.S. shutoff tool (YM-08025) (3)

6.     Start the engine and let it warm up.

7. Inspect:
• Idle speed

Out of specification — Turn throttle stop screw (1) to adjust.

Idle Speed
1,050 ±50 r/min

8. Adjust:
• Carburetor synchronization

Carburetor synchronization adjustment steps:

•  Synchronize the carburetor No. 1 to the carburetor No. 2 by turning the synchronizing screw (1) until the both gauge readings are the same.

•   Rev. the engine for a fraction of a second, two or three times, and check the synchronization again.

Vacuum Pressure at Idle Speed:
23.99 kPa (180 mm Hg, 7.09 in Hg)

Vacuum Synchronous Difference: 
0.67 kPa (5 mm Hg, 0.2 in Hg)

•   Repeat the above steps to synchronize the carburetor No. 4 to the carburetor No. 3 by turning the synchronizing screw (3) until the both gauge readings are the same.
•   Repeat the same steps to synchronize No. 3 carburetor to No. 1 carburetor, then turn synchronizing screw (2) until both gauge readings are the same.