SIMONINI 250 User manual

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SIMONINI 250

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This handbook aims to bring to the attention of key technical, functional and maintenance of your Simonini 250 engine. Read carefully the following
pages, will be synonymous with safety, reliability and great satisfaction durable.
This manual is considered part of the Simonini 250 engine, in case of transfer, please deliver it to the new owner. All the information available at the time
printing have been printed in this manual. SIMONINI S.r.l. reserves the right to make modifications or changes without prior notice.
TECHNICAL DATA
BORE
70mm
STROKE
60mm
DISPLACEMENT
230,8cc
COMPRESSION RATIO
10,1/1
WEIGHT READY TO FLY
17,3Kg
CONSUMER A 5000 rpm
4litri/h
POWER 8000 rpm
33hp
STATIC THRUST
88Kg
Lamellar intake with Walbro Carburetor WB37
Aluminum cylinder with ceramic coating magnesium,
Exhaust resonance
Poly-V belt reduction
Electronic ignition
Electric start
Alternator battery charger in flight
Lubrication premix: 2%
Airbox
Available in the following versions:
250 Standard: Electric starter
250 Light: Pull start (without battery recharge)
250 Dual starter: Electric starter and pull start

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MINI2EVO/01
RECTIFIER RE-CHARGE BATTERY
MINI2EVO/34
PULLEY SPACER 12X 34 X 4
SIM250/02
COIL
MINI2EVO/35
KIT BEARINGS FOR BIG PULLEY 6204 2RS
MINI2EVO/03
KIT SCREWS FOR HEAD (4) M8 X 23
MINI2EVO/36
BEARINGS SPACER 20 X 27 X 10
MINI2EVO/04
HEAD
MINI2EVO/37
PULLEY SEEGER 47 X 1,75
MINI2EVO/05
CYLENDER HEAD GASKET 81 X 2
MINI2EVO/38
ECCENTRIC PINION
MINI2EVO/06
KIT SCREWS FOR CYLINDER M8 X 1,25 X 56
SIM250/39
ECCENTRIC DISTANCE
MINI2EVO/07
CYLINDER
SIM250/40
KIT SEALS 25 X 40 X 7
MINI2EVO/08
CYLINDER GASKET
MINI2EVO/41
KIT BEARINGS FOR CRANKCASE 4205 - 6205/C3
SIM250/09
KIT SILENT-BLOCKS (4) M8 30 X 30
MINI2EVO/42
COMPLETE CRANKSHAFT AND ROD
SIM250/10
CRANK-CASE
MINI2EVO/45
COMPLETE CONNECTING ROD
SIM250/11
KIT ENGINE SCREWS
MINI2EVO/46
COMPLETE PISTON AND RINGS MM. 70
MINI2EVO/12
WASHER-PRESSURE OUTLET
MINI2EVO/46A
TWO RINGS MM. 70
A71
AIRBOX
MINI2EVO/46B
PISTON PIN 18 X 56 X 13
A73
SPONGE FOR AIRBOX
MINI2EVO/46C
TWO CLIPS 18 X 1,25
A74
RUBBER FOR AIRBOX
MINI2EVO/47
STATOR
A75
CLAMP FOR AIRBOX
MINI2PLUS/48
MINI2EVO/17
CARBURETTOR WALBRO WB 37
MINI2EVO/49
FLY-WHEEL
MINI2EVO/17C
GASKET FOR CARBURETTOR
MINI2PLUS/50
ALUMINIUM PLATE FOR COIL
MINI2EVO/17D
ALUMINIUM AIR FILTER
MINI2EVO/51
LITTLE PINION FOR REDUCTION
MINI2EVO/17E
KIT SCREWS FOR CARBURETTOR (2) M5 X
50
MINI2EVO/52
SPARK PLUG BR 10 ES
SIM250/18
KIT SCREWS CARB. RUBBER MANIFOLD
(2X25- 2X30)
MINI2EVO/53
ALUMINIUM PLATE FOR COIL
SIM250/19
KIT SCREWS FOR COIL (2X20 mm)
SIM250/54
EXHAUST SISTEM
SIM250/20
RUBBER MANIFOLD
SIM250/54A
EXHAUST BEND
MINI2EVO/21
REED VALVE
SIM250/54B
SILENCER
MINI2EVO/22
REED VALVE GASKET
SIM250/54C
STAINLESS STEEL CLAMP FOR SILENCER
MINI2EVO/23SIL
ELECTRC STARTER
SIM250/54D
EXHAUST EXPANSION
SIM250/23 A
STARTER MOTOR BRACKET
SIM250/54E
KIT SPRINGS EXHAUST
SIM250/23 B
KIT SPACER STARTING MOTOR. (2)
SIM250/56
ENGINE SUPPORT PLATE
MINI2EVO/26SIL
CROWN GEAR
SIM250/57
KIT SPACER ENGINE SUPPORT PLATE (4)
MINI2EVO/27
WASHER FOR PINION
MINI2EVO/58
RUBBER FOR SPARK PLUG
MINI2EVO/28
NUT FOR PINION AND FLY WEEL
MINI2EVO/59
CONNECTING ROD CAGE 16 X 20 X 20
MINI2EVO/29
POLY-V BELT PJ 508
MINI2EVO/60
EXHAUST GASKET
SIM250/30
ALUMINIUM PLATE FOR PROP. AND
SCREWS
MINI2EVO/61
COMPLETE GASKET KIT
MINI2EVO/32
SCREW FOR BIG PULLEY
SIM250/62
EXHAUST MANIFOLD AND SPRINGS
MINI2EVO/33
BIG PULLEY FOR REDUCTION 1:248 / 1:268
/ 1:293
SIM250/63
EXHAUST SILENT-BLOCKS (2) M8 30X30 / M8 30 X 20
MINI2EVO/33A
BIG PULLEY FOR REDUCTION 1:265/ 1:287
/ 1:313
MINI2EVO/64
KIT SCREAW CYLINDER (4) M8 X 55

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TIGHTENING TORQUES
Description
Number in table
NM
Kgf.m
Head Nut
6x40 Screws
Connector
6x30 Screws
6x25 Screws
12 Nuts
12x30 Screws
8x40 Screws
Spark Plug
8X55 Screws
3
11
12
18
18
28
32
39
52
64
22
12
10
12
10
54
60
32
18
35
2.2
1.2
1.0
1.2
1.0
5.4
6.0
3.2
1.8
3.5
ELECTRICAL DIAGRAM

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INSTALLATION
The SIMONINI 250 engine have to be fitted to the frame using its four elastic supports
"silent blocks", radial mounted, positioned on the support, which are a protection for the
electronic ignition.
During the installation, some safety precautions have to be followed: remember that an
engine generates vibrations, even if very small, which can cause the loosening and/or
removal of screws or any other object. Therefore, to prevent any engine components
may cause damage to persons and/or properties, make sure the engine through a small
steel cable. Components normally "made safe" are:
• The AIR BOX and the carburetor to the engine
• The springs and exhaust to the engine
• The engine itself to the frame, bypassing the silent blocks. In this case we will use the
"webbing" of synthetic fiber is particularly resistant to traction and tearing.
The mouth of the spherical muffler should be lubricated with grease resistant to high
temperatures (e.g. copper grease) before being implanted in the exhaust manifold.
We recommend taking maximum care when carrying out these operations: in any case,
during the assembly phase the proper choices must be made by expert and qualified
personnel.

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FUEL
The SIMONINI 250 engine has been designed to operate with a gasoline/oil mixture.
We recommend using synthetic oil, remains mixed with gasoline in the tank for a
longer period. It grants good lubrication and longer life to engine components.
During the running-in stage, use an oil percentage of 2,5% and then move to 2% once
the stage has been completed.
The gasoline must have an octane number that is not lower than 95, in order to avoid
pre-ignition phenomena.
Carefully mix the fuel oil in a tank is appropriate and it is better, once mixed, to use it
within one week.
Do not use vegetable or animal oil.
DO NOT MIX DIFFERENT TYPES OF OIL.
CARBURETOR
The carburetor Walbro WB37, if used properly, provides excellent performance
requiring few tuning interventions. However, changes in weather conditions, altitude
and a possible change of the propeller (in both size and pitch) can affect its functioning.
The carburetor requires an adjustment during the testing phase with a standard setting
• Screw H "affects the entire range of use of the engine”. From completely tightened,
loosen by 1 turns or 360 °.
• Screw L “only has as effect at a low engine speed”. From completely tightened,
loosen by ¾ turns or 270 °.
Given the fact that the first test is performed at an altitude of 750 m above sea level,
you may need to depart from this setting without the adjustments exceed the limit:
• screw H do not fall below a round 360 °
• Screw L do not fall below ½ turn 180 °

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The carburetor is equipped with a depression pump to remove fuel from the tank, but
do not exceed the height difference between them as it has not exceed to 50-60cm. The
same applies to the tube: Do not exceed 50-60cm.
You may inserted a manual pump between the tank and carburetor, to make the mixture
reach the carburetor before the start, avoiding stress to the starter.
CARBURATION
NB: in this paragraph the words "MIXTURE" indicates the union of the two elements (AIR) + (OIL
/GASOLINE) which takes place inside the carburetor.
Weather conditions or altitude changes have influence to the operation of the engine
as it varies the air density and, consequently, changes the mix ratio between the
element AIR and the element OIL /GASOLINE.
In general, we can say that at high altitude, high humidity or high temperatures, less air
enters and therefore the mixture is richer in oil/gasoline: you will have to re-establish
the proper relationship by screwing the two screws "H/L”.
In contrast, with low temperatures and low humidity, the air will become denser than
the lean-burn oil / gasoline, and consequently you will have to unscrew the two screws
"H / L".
WARNING: A mixture that is too low in oil/gasoline causes considerable damage to the
engine, which can cause it to break down and/or stop suddenly. It is recommended to
carry out the carburetion operations with the ENGINE SWITCHED OFF.
When the "H / L" screws are tightened/loosened, carry out variations of 1/8 of a turn
each time or "45°", larger movements in a turn can cause engine damage.

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RUNNING-IN
WARNING
• Before starting the engine, make sure that there are no loosened screws or
improperly attached parts;
• Ensure that any persons are at a distance of absolute safety and never in range of the
propeller;
• Do not start the engine where there are rocks or other objects that the force
generated by the propeller can lift and throw even at a considerable distance;
• Do not start the engine without propeller or without exhaust;
• Do not start the engine indoors: the exhaust gases contain poisonous carbon
monoxide which is toxic and can cause loss of consciousness and death. The engine,
before being sold, was subjected to a pre-running-in to verify the proper operation and
a test that confirms all the features advertised.
Once you require a SIMONINI 250, you should pay particular attention to the first hour
of operation, in order to ensure all the engine’s qualities over time.
DURING THE RUNNING-IN PHASE, KEEP PARTICULAR ATTENTION TO THE EXHAUST GAS
TEMPERATURE AND HEAD TEMPERATURE UNDER CONTINUOUS OBSERVATION.
Having selected a suitable place and above all free from gravel or other materials that
may damage the moving parts, start the engine and let it warm up for 10 minutes at
2500 rpm, then slowly bring the engine to a system more high, decreasing and
increasing the speed at intervals of 1 minute, thus going to affect various "range" of
use, but without exceeding the 4500 rpm. Absolutely avoid the constant and repeated
closing/opening the gas valve. After about 20 minutes from start-up, shut down the
engine and let cool completely.
WARNING! When the engine is running and even after its shutdown, it can cause
burns: so make sure it is completely cooled before working on it.
Proceed with a thorough visual inspection of any anomalies or loose parts. Once you
make sure everything is working properly and there are no problems of any kind, you
must repeat the previous operation for another 20 minutes of running, respecting the
same indications.

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Last running-in phase: warm up the engine again for 10 minutes at 2500 rpm and then,
as in the two previous operations, gradually increasing the rmp. Now you can wander
over the entire range of use of the engine, bringing it several times to the maximum
speed at intervals of 1 minute.
After 20 minutes you can turn off the engine and, once cooled, you will proceed to a
full-tightening the screws on the SIMONINI 250. Now the engine SIMONINI 250 will be
ready for use for which it was designed by continuing to use a percentage of oil by 2%.
WARNING! DURING THE RUNNING-IN PHASE, KEEP PARTICULAR ATTENTION TO THE EXHAUST GAS
TEMPERATURE AND HEAD TEMPERATURE UNDER CONTINUOUS OBSERVATION.
MAINTENANCE
Each time you use the engine, remember to perform routine checks pre-start-up:
• Check the silent block condition in complete integrity
• Make sure the exhaust does not present any cracks
• Ensure that the propeller does not present cracks or dents
• Make sure you have enough fuel, according to the duration of intended use of the
engine.
• Check that the electrical system and cables do not show abrasions or disruption.
• Check that there are no screws or parts loosened.
BELT TENSION
WARNING: CARRY OUT THE OPERATIONS WITH THE ENGINE SWITCHED OFF AND COOLED DOWN
During operation, the belt is under strain and wear and as result, lengthening occurs,
which could lead to sliding on the pulleys, with a subsequent decrease in the general
engine performance.
To restore the proper tension, loosen the screw M8 (No. 39) on the foot of the engine
which fastens the pulley can, turn screw M12 (n°32) anti-clock wise using force of 1.8
Kgm and then re-tighten screw M8 (n°39)
n°39).

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INTERVENTIONS EVERY 20 HOURS
• Clean filter carburetor
• Clean fuel filter
• Check the belt tension and condition
• Lubricate the ball joint of the muffler
INTERVENTIONS EVERY 60 HOURS
• Replace the engine and exhaust silent blocks
• Replace the transmission belt
• Check the status of the intake manifold rubber
• Replace the exhaust pipe sound-absorbent material
• Check the electrode gap spark-plug: if it is over 0.6 mm, change the spark plug
• Rubber components such as belt transmission, silent block, intake manifold and
depression tube may be damaged by atmospheric agents. Their durability can
therefore be different from what is reported, you should therefore check their
condition and provide a possible replacement even outside the agreed time.
INTERVENTIONS EVERY 200 HOURS
• Replace all the bearings (N°35 + N°41)
• Replace all oil seals (N°40)
• Check the internal parts of the engine and carry out their replacement in case
the height limit confirm it is necessary.
•Cylinder:
-must not show signs of seizure or scratches on the filling material (nickel silicon);
-check the wear of the cylinder in the point 3 (shown in diagram 1) on X and Y
axles, none of the heights obtained must exceed the height limits:
cylinder SELECTION A: 70.03mm
cylinder SELECTION B: 70.04mm
cylinder SELECTION C: 70.05mm
The selection is shown with a letter at the bottom of the cylinder

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disegno 1
• piston:
-There must not be any signs of seizure or deep cracks.
-Check the wear by measuring the piston at 21,7mm from the bottom keeping the
measuring instrument at a right angles to the axis pin.
Height limits:
SELECTION A: 69.89mm
SELECTION B: 69.90mm
SELECTION C: 69.91mm
• The pin must not be blue because that indicates a high working temperature and the
external diameter must not be less than 17.990mm.
• Measure the slack between the piston ring and its seat: slack height limit 0.1mm.
• Piston ring: insert a piston ring in the cylinder one by one, by using the piston, so it is
a square, measure the gap that is created between the two ends of piston ring using
feeler gauge. Height limit: 0.7mm
• Crankshaft: supporting the crankshaft at the two working points of oil seals, with two
comparators, measure the centering at the two working points of the bearings, marked
on diagram 2 with the letter A. Height limit: 0.05mm

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disegno 2
• Measure the bearing seating, which must not be lower than the height limit:
24.98mm
• Check with a feeler gauge that the axle slack of the connecting-rod between the two
semi shaft, which must not exceed the height limit: 0.7mm
• Check the radial slack of the connecting rod on the coupling axle which must not
exceed the height limit: 0.05mm. This is detected by placing a comparator (B), as
shown in diagram 2, and moving the connecting rod vertically. The slack shown by the
comparator is assessed. Measure the diameter of the hole in the connecting-rod foot.
Height limit: 20.00mm
• Reed valve: Verify that between the frame and the reeds there is no space(diagram 3)
Height limit: 0.2mm.

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WARNING: The reeds should not and cannot be turned (diagram 4)
TEMPERATURE
The SIMONINI 250 has been designed to work under certain operating temperatures: so
please stick strictly as written.
Temperatures that must not be exceeded when cruising or when the engine is at a fixed
rpm for a long time:
• Exhaust gas temperature 580°C.
• Temperature under spark plug 170° C.
Temperatures that must not be exceeded when taking off or when all the power is
required to the engine:
• Exhaust gas temperature 600° C.
• Temperature under spark plug 200° C.
WARNING engine will NEVER, at any time and condition, exceed:
• 600 ° C temperature of the exhaust gas.
• 200 ° C temperature under spark plug
It therefore makes it appropriate to adopt an instrument that detects these temperatures
for the protection of the engine, but especially for your and others' safety.
We also inform you that high exhaust gas temperatures, in many cases, are a symptom
of poor carburetion. While high temperatures under the spark plugs, usually, are due to
poor ventilation (heat dissipation) of the engine, caused by the presence of bodies and
/ or materials that prevent the passage of air cooling

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COMPONENTS AND TOOLS ON REQUEST
To have the possibility to customize the engine and then adapt it to different needs and
methods of use, SIMONINI offers a range of components on request:
PULEGGIA MOTRICE
PINION
In four different diameters (44/48/53/55/56) as well as providing the proper reduction
ratio, can be used to soften or make more rapid rise in engine speed or to move,
maintaining the propeller revolutions, any points of the torque curve that does not meet
your needs at a specified "range" of use, as when cruising.
Cod: SIM250/51 mm. 44
Cod: SIM250/51 mm. 48
Cod: SIM250/51 mm. 53
Cod: SIM250/51 mm. 55
Cod: SIM250/51 mm. 56
PROPELLERS
For this engine we recommend a carbon fiber propeller developed in collaboration with
the Helix company:
H 30 F 1,25m L-M-09-2 suitable for reduction 1:268
H 30 F 1,30m L-M-08 -2 suitable for reduction 1:248
H 30 F 1,30m L-M-10 -2 suitable for reduction 1:268
H 30 F 1,40m L-EZ-07 -2/A6 suitable for reduction 1:268

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AVAILABLE REDUCTION REPORTS
1:248 Big pulley 129 mm / Pinion 52 mm
1:268 Big pulley 129 mm / Pinion 48 mm
1:293 Big pulley 129 mm / Pinion 44 mm
1:265 Big pulley 138 mm / Pinion 52 mm
1:287 Big pulley 138 mm / Pinion 48 mm
1:313 Big pulley 138 mm / Pinion 44 mm
MAINTENANCE TOOLS
To facilitate maintenance operations, we propose two distinct tools with the aim of
extracting the ignitions flywheel and engine pulley:
Code U02 Fly-wheel extractor
Code U06 Pinion extractor for diam. 53 / 55 / 56
Code U07 Pinion extractor for diam. 44/48 ratio

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REQUEST FOR REPAIR OR REPLACEMENT OF WARRANTED
ATTENTION
The warranty is valid for 12 months from date of purchase and it covers all the engine
parts. It does not include the parts subject to wear: cylinder Nikasil, piston and drive
belts. There is NO warranty if the engine is tampered or if any not original parts has
been fitted without our approval.
In the case you need, please send the engine to
SIMONINI RACING srl
indicating:
• name
• address
• number of motor
• date of first start
• hours of operation
• any previous repairs
• carburetion setting
• complete description of the problem
Thank you for your trust and we remind you that the staff of SIMONINI RACING srl will be at your
disposal for any questions.
SIMONINI RACING SRL
Via Per Marano 4303, Loc. San Dalmazio - 41028 Serramazzoni (Mo)
Tel. [phone] Fax. [phone].
Http : www.Simonini-flying.com E-mail : [email protected]

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