-6-
(6) Occasionally tighten the prop nut and exhaust nut.
(7) Take an extreme care for safety when operating the engine or flying the model airplane not to bother others.
(8) An engine for a model airplane is not a toy. Handle it with an extreme care.
(9) After completing ground break-in or operating the engine for 1 hour, adjust tappet gaps (valve clearances) by following
procedure to compensate initial wearing, while the engine is cold.
#1 cylinder should be adjusted first, next #3, finally #2 cylinder should follow in order by the same procedure.
(a) Remove the plug and rocker covers from the #1 cylinder.
(b) Turn the prop slowly forward by hand until the rocker arm of intake stops. Further turn the prop to bring the piston to
the TDC (Top Dead Center) of compression stroke.
(c) Use the attached wrench and hexagonal wrench to adjust the gaps indefi-
nitely close to zero within the range compression exists. If the gap is lower
than 0, the valve has to be opened at all phases so the compression
doesnʼt occur (then, loosen the screw to reset).
After adjustment, put on the spark plug and turn the prop forward to check
if the compression is enough.
(d) Checking the gap, securely tighten (but not excessively) the lock nut.
(e) Do the same adjustment for #3 cylinder.
(f) Finally do the same adjustment for #2 cylinder.
* In the case of the engines for vehicle, small gap is given to tappets to absorb valve elongation. However for 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 when the engine is cold.
(10) Since the fuel contains more than 5% of oil, sometimes the exhaust valve gets dull by carbon or sludge especially in cold
atmosphere. Then turn off the ignition switch and rotate the prop by electric starter. After dilute the oil content by this way,
remove the fuel from inside the carb and the engine. It helps the valve to move smoothly.
Or, remove the rocker cover and applying some anti-rust spray to the exhaust valve is effective as well.
(11) Please notice that our guarantee will not cover any breakage or trouble on the engine
caused by userʼs disassembling or modification.
(12) Notes for purchasing parts:
Please give orders to the shop you purchased from with “Engine model”, “Part No. or part name”, and “Quantity”.
Optional parts
・Filter with weight [36-154]
・Neoprene tube for gasoline(1m) [36-155]
・Spark plug CM-6 [36-120]
・Aluminum spinner nut [57T-30]
・Cooling cover （1pair) [120S-166]
・Tappet adjusting kit [120S-161]
・Digital tachometer [17-168]
Tappet adjustment
Fig.11
Must not be inserted
(over gap)
Limit gauge
(0.1mm)
Close to "0" with no limit
Note: 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 factors in the
maintenance of 4-stroke engines. Operating the engine with the tappet gap enlarged excessively will cause poor performance or troubles.
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: 047-378-2459 FAX: 047-378-4155
http://www.saito-mfg.com
