- Remove the seat. (6-4)
- Lift and support the fuel tank. (4-51)
- Remove the fuel tank side covers, cowlings and inner cover. (6-6)
- Remove the radiator. (5-4)
- Remove the spark plugs. (2-6)
- Remove the cylinder head covers.
The tappet clearance specification is different for intake and exhaust valves.
Tappet clearance must be checked and adjusted, 1) at the time of periodic inspection, 2) when the valve mechanism is serviced, and 3) when the camshafts are disturbed by removing them for servicing.
Tappet clearance (when cold):
- IN. : 0.10 - 0.20 mm (0.004 - 0.008 in)
- EX. : 0.20 - 0.30 mm (0.008 - 0.012 in)
Note:
- The tappet clearance should be taken when each cylinder is at Top Dead Center (TDC) of compression stroke.
- The cams (IN & EX) on the front cylinder at position А show the front cylinder at TDC of compression stroke.
- The cams (IN & EX) on the rear cylinder at position В show the rear cylinder at TDC of compression stroke.
- The clearance specification is for COLD state.
- To turn the crankshaft for clearance checking, be sure to use a 17-mm wrench, and rotate in the normal running direction. All spark plugs should be removed.
- Remove the generator cover plug 1 and timing inspection plug 2
- Turn the crankshaft to set the No. 1 (Front) cylinder at TDC of compression stroke. (Align the "F | T" line on the generator rotor to the index mark of valve timing inspection hole and also bring the camshafts to the position as shown in page 2-8.)
- To inspect the No. 1 (Front) cylinder tappet clearance, use a thickness gauge between the tappet and the cam. If the clearance is out of specification, adjust it into the specified range.
- 09900-20803: Thickness gauge
- Turn the crankshaft 270 degrees (% turns) to set the No.2 (Rear) cylinder at TDC of compression stroke. (Align the "R | T" line on the generator rotor to the index mark of valve timing inspection hole and also bring the camshafts to the position as shown in page 2-8.)
- Inspect the No. 2 (Rear) cylinder tappet clearance as the same manner of No. 1 (Front) cylinder and adjust the clearance if necessary.
- 09900-20803: Thickness gauge
Tappet clearance adjustment
The clearance is adjusted by replacing the existing tappet shim by a thicker or thinner shim.
- Remove the intake or exhaust camshafts. (3-20)
- Remove the tappet and shim by fingers or magnetic hand.
- Check the figures printed on the shim. These figures indicate the thickness of the shim, as illustrated.
- Select a replacement shim that will provide a clearance within the specified range. For the purpose of this adjustment, a total of 25 sizes of tappet shim are available ranging from 2.30 to 3.50 mm in steps of 0.05 mm. Fit the selected shim to the valve stem end, with numbers toward tappet. Be sure to check shim size with micrometer to ensure its size.
Refer to the tappet shim selection table (Pages 2-11 and -12) for details.
Note:
- Be sure to apply engine oil to tappet shim top and bottom faces.
- When seating the tappet shim, be sure to face figure printed surface to the tappet.
Caution: Reinstall the camshafts as the specified manner. (3-105)
- After replacing the tappet shim and camshafts, rotate the engine so that the tappet is depressed fully. This will squeeze out oil trapped between the shim and the tappet that could cause an incorrect measurement, then check the clearance again to confirm that it is within the specified range.
- After finishing the tappet clearance adjustment, reinstall the following items.
- When installing the cylinder head cover, do not forget the gasket А.
- Cylinder head cover — 3-111
- Spark plug and plug cap — 2-8
- Valve timing inspection plug — 3-111
- Generator cover plug — 3-112
Tappet shim selection table (intake)
Tappet shim No. (12892-41C00-XXX)
How to use this chart:
- I. Measure tappet clearance. "ENGINE IS COLD"
- II. Measure present shim size.
- III. Match clearance in vertical column with present shim size in horizontal column.
Example
- Tappet clearance is — 0.23 mm
- Present shim size — 2.70 mm
- Shim size to be used — 2.80 mm
Tappet shim selection table (exhaust)
Tappet shim No. (12892-41C00-XXX)
How to use this chart:
- I. Measure tappet clearance. "ENGINE IS COLD"
- II. Measure present shim size.
- III. Match clearance in vertical column with present snim size in nonzontai
Example
- Tappet clearance is — 0.38 mm
- Present shim size — 2.90 mm
- Shim size to be used — 3.05 mm