plug is in good condition.

Fill the crankcase through the oil filler opening with approximately 1.5 U.S. pts. (0.7 liter) of recommended grade oil. Check the oil level with filler cap dipstick, however, when making this check, do not screw in the cap. Oil level should be between the upper and lower oil level markings (2), (3) on the dipstick.

Note:

  1. Do not operate the engine if the oil level is below the lower

oil level mark (3) on the dipstick.

2. When operating the motorcycle under unusually dusty condition, it

is recommended that the oil change be performed at more frequent intervals than that which is specified in the maintenance schedule; this will have a very beneficial effect on the engine.

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Oil Drain Plug

SPARK PLUG CLEANING AND ADJUSTMENT

The NGK C-7HS or ND U-22 FS plug is used as standard equipmenl on this model. Servicing of the spark plug is as follows.

1. Detach the high tension cord from the spark plug and remove the spark plug with the special wrench provided in the tool kit.

  1. Inspect the electrodes and center porcelain of the spark plug for deposits, crrodcd eleclrodes, or carbon fouling. If the spark plug deposits are heavy, or the electrodes appear to be crroded exccssively, replace the spark plug vvith a new one. If the spark plug is carbon or wet fouled. the

plug can sometimes be cleaned with a stiff wire such as a pin.

  1. Adjust the spark plug gap to 0.024-0.028 inch (0.6-0.7 mm). The gap can be measured with a thickness gauge. The adjustment is by bending the negat ive (grounded) electrode (2)

'I. When installing the spark plug, do not over tighten.

Note: 1. Never use an improper heat range spark plug.

2. Do not attempt to dry or remove soot from the spark plug by burning

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CD

Spark plug gap Negative electrode

IGNITION TIMING ADJUSTMENT

Adjustment of contact breaker point gap and ignition liming are required to maintain satisfactory engine performance.

'1. Remove the left crankcase cover.

2. Rotate the flywheel counterclockwise to find the point where the breaker
Point gap is at maximum and check if the gap is incorrect using a thickness gauge

  1. The standard gap is 0.012-0.016 in. (0.3-0.4 mm).

Breaker Point Gap
Breaker locking screw

  1. When adjustment is necessary, loosen the breaker locking screws, and move the breaker base in either clockwise or counterclockwise direction to obtain the standard point gap setting.
  2. After completing the breaker point gap adjustment, recheck the ignition timing. To perform the check, rotate the flywheel so that when the flywheel "F" timing mark (4) is aligned to the timing index mark (3) on the left crank case, the breaker points just begin to open.

30

VALVE TAPPET CLEARANCE AD JUSTMENT

Excessive valve tappet clearance will cause tappet noise, and negative clearance will cause valve damage and low power. Therefore, the valve tappet clearance should be maintained properly. Adjustment should be made with the engine cold.

  1. Remove the tappet adjusting hole caps.
  2. Remove the left crankcase cover.
  3. Rotate the flywheel counterclockwise until the "T" mark on the flywheel lines up with the index mark (1) on the crankcase flange.

In this position, the piston may either be on the compression or the exhaust stroke. The adjustment must be made when the piston is on the top dead

center of the compression stroke, that is when both valves are closed. This condition can be determined by shifting the tappets with fingers through the tappet adjusting holes and if the tappets are free, it is an indication that the valves are closed and that the piston is on the compression stroke.

If the tappets are tight, the valves are opened, so rotate the flywheel 360 degrees and realign the "T" mark to the index mark.

3'

  1. The valve tappet clearance is measured between the valve stem lind tappet adjusting Screw. Both the inlet and the exhaust valves should be adjusted to 0.002 in. (0.05 mm). To periorlll the adjustment. loosen the lock nut (1)and turn the adjustmg screw (3) Turning the adjusting screw in the clockwise direct ion will reduce the clearance.

Note:

Make sure that the adjustment has not been disturhed while tightening the lock nut,

by rechecking the clearance after the lock nut has been tightened.

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Adjusting screw
Adjusting screw lock nut
Thickness gauge

AIR CLEANER SERVICE

A clogged air filter will adversely affect engine performance, therefore should be cleaned periodically as follows.

1. Unscrew the air cleaner cover setting screw and remove the air cleaner cover (1)

  1. Remove the air cleaner element (2).

3, Wash the air cleaner element with gasoline and dry it thoroughly.

4. Soak the air cleaner element in a mixture of 10 part gasoline to 1 part of engine oil, curing out by hand and then reinstall into the air cleaner case.

33

Air cleaner cover
Air Cleaner Element

THROTTLE CABLE ADJUSTMENT

For safe, positive and consistent engine response the good condition and operation of the throttle grip and throttle cable is a must.

1. Check for Ihe smooth rotation of the throttle control grip from the full open to the full close positions. Check when at full left and full right steering positions.

  1. Standard throttle grip free play is approximately 10-5 degrees of the grip rotation.

If grip free play rotation exceeds, this adjustment of the throttle cable

adjuster (2) is necessary. Turn the cable adjuster until grip free play rotation is reduced to 10-15 degrees.

Rubber cap
Throttle cable adjuster

34

CARBURETOR ADJUSTMENT

Perform the carburetor adjustment periodically as necessary.

Make the carburetor adjustment after the engine attains operating temperature.

1. Adjust the engine idle speed to approximately 1,300 rpm with the throttle stop screw (1)

2. Turn the air screw slowly back and forth to obtain the point of the highest engine rpm.

3. If the idling speed increases excessively, reduce the speed with the throttle stop screw. then recheck the air screw.
Repeat the above procedure again if necessary to obtain a stable adjustment

35

Throttle stop screw
Air screw

FUEL STRAINER SERVICE

The fuel strainer is incorporated in the right side of the carburctor. Accumulalion of dirt in the strainer will restrict the flow of the fuel and cause the carburetor to malfunction. therefore, the fuel strainer should be serviced periodically.

1. Turn the fuel valve to the 5 position. (page 17)

2. Remove the fuel strainer cover and o-ring seal (1)

The screen fuel strainer (2) can be removed from the carburetor wash in solvent or gasoline and reassemble.

36

O-Ring Seal
Fuel Strainer