Saito FA-120 Special Instruction Manual download pdf (Page 8)

Valve/Tappet Gap

Adjustment

After approximately one hour of

operation, tappet gap adjustment may be

necessary. When you check the valves,

lubricate the moveable parts. Also make

sure the screw is in tight before making

adjustments to valves.

Adjust the valves to a clearance of

.03mm to .10mm (.002 to .004 in) using

the supplied gauge. The valves must

be adjusted with the engine cold due to

thermal expansion.

Note: Valves must be in the compression

stroke or closed position as shown in

the following figure. When adjustment

is completed, make sure you tighten the

lock nut.

How to Adjust

Remove the plug and the rocker arm

cover and revolve the propeller slowly

clockwise by hand. The intake side

rocker arm stops, and by turning it, the

piston reaches the compression top dead

center (TDC).

In that position, adjust with the included

gauge and hexagonal wrench so tappet

gap may be set to almost zero when the

engine is in the compression stroke. If

the gauge can enter (a limit gauge with

a 0.1 mm thickness), the clearance is at

maximum and needs adjustment, adjust

between 0.03 and 0.10mm (0.002 to

0.004 in.) After the gap is checked,

tighten the locknut securely. Do not

over-tighten.

The tappet gap is the most important

factor in the maintenance of 4-stroke

engines, and operation with an excess

clearance will degrade performance.

In particular, a large gap aggravates

abrasion of the tappet and the cam and

also increases the unusual sound.

Carburetor

Maintenance

Should you experience difficulty with

the carburetor of your engine:

• Factory settings for the idle needle

valve are about 4 turns out from a fully

closed position.

• The high-speed needle valve is set to

about 2 1/3 turns out from a fully

closed position and is a good point to

start from.

Generally speaking, there are very few

things that will keep today’s modern

gasoline engines from starting. To that

end, make sure you are using good-

quality “fresh” fuel, the spark plug is

good, and the ignition system is working

properly.

Check the battery voltage to make

sure the ignition is getting the proper

voltage. Should the engine fail to start

after these items are verified, refer to the

Troubleshooting Guide on page 11.

Tappet Adjustment

Adjust between

0.03 – 0.10mm (.002 in – .004 in)

Gauge

(0.1mm Max.)

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NOTES 1312 VALVE/TAPPET GAP ADJUSTMENT

14387 SAI FG_20andFG_36 Manual.indd 12-13 12/16/08 2:09:13 PM

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