-4-
Tappet adjustment
I. Normal Operation and Maintenance
(a)
Do not operate your engine too lean at full throttle since the engine might be overheated.
Adjust the main needle slightly open than the peak. (Too lean operation causes knocking,
stoppage or negative influence on the connecting rods and cam gear.)
(b)
After completing ground break-in or operating the engine for one hour, adjust tappet gaps
(valve clearances) by following procedure to compensate initial wearing, while the engine is
cold.
1.
Remove plugs and rocker arm covers of all cylinders.
2.
For instance start adjusting from the No.1 cylinder. Turn the prop slowly forward by
hand, to stop the rocker arm of the No.1 cylinder.. Further turn the prop, to bring the
piston to the TDC (Top Dead Center) of compression stroke.
3.
Use the attached wrench and hexagonal wrench to adjust the gaps indefinitely close to zero within the range compression exists.
4.
On checking the gap, securely tighten (but not excessively) the lock nut.
* In the case of the engines for vehicle, small gap is given to tappets to absorb valve elongation. In the case of SAITO engines, gap becomes larger during operations
due to thermal expansion of the cylinder (made of aluminum). Therefore set the gap indefinitely close to zero while the engine is cold.
(c)
Lubricate the rocker arm and valve area at inspection as required.
(d)
When connecting the exhaust pipe to the cylinder or attaching the prop nut, apply thin coat of silicon rubber (not excessively) on the thread section before tightening.
This prevents leakage or loosening.
(e)
Occasionally tighten the prop nut and exhaust nut (while it is hot).
(f)
After a flight, lubricate the entire engine with spray type preserve lubricant through the carburetor or breather.
(g)
If the engine in not operated for longer period of time, lubricate the entire engine before placing a plastic cover on.
J. Internal Lubrication of Engine and Waste Oil Disposal
Oil contained in fuel enters into the crankcase through the clearance between the piston and cylinder to lubricate the piston, connecting rod, bearings, cams and gears. Waste
oil is discharged from the breather nipple located at the lower part of crankcase. Connect a silicone tube to the breather nipple and clamp the other end of tube at the end of
exhaust pipe by using bands.
k. Supplementary Notes:
(a)
Precautions for wiring of attached connector set to heat plugs:
To equalize current, bind cables without cutting them even if it’s long.
* The engine adjusted properly does not require plug heating at idling (2,000-2,500rpm) once it starts.
(b)
Causes of reversing at starting:
Priming amount is inadequate.
Manual-cranking speed is insufficient.
Voltage or current for plug heating is low.
(c)
Please notice that our guarantee will not cover any breakage or trouble on the engine caused by your disassembling or modification.
If disassembling becomes necessary, observe the following precautions.
(d)
Notes for purchasing parts:
Please give orders to the shop you purchased from with a sheet with engine name, part name or number, and marking (alphabet on the lower face of rear cover).
(e)
Take an extreme care for safety when operating the engine or flying the model airplane not to bother others.
(f)
An engine for a model airplane is not a toy. Handle it with an extreme care.
All specifications and models are subject to change without notice.
SAITO SEISAKUSHO, CO., LTD.
22-7, 3-chome, Tokagi, Ichikawa-shi, Chiba prefecture 272-0024, Japan
Phone: 047-378-4156
FAX: 047-378-4155
Occasionally check tappet gap by those procedure. When the attached gauge (limit gauge, t=0.1mm) comes to be inserted, gap has been enlarged beyond the allowable
limit. Make an adjustment to lessen the gap. Tappet gap is one of the most important factor in the maintenance of 4-stroke engines. Operating the engine with the tappet
gap enlarged excessively will cause poor performance or troubles.
