Marc Motor ROS Series Release Note
MADE IN ITALY
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ROS motor
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Technical handbook
Tel. & Fax +39 0733 493158 - email: rosmotor@marcmotor.com - web: www.rosmotor.it
Via dei Velini, 293 - 62100 Macerata (MC) - Italy
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Index
Index 2
Introduction 3
General advice 4
Component description 5
Head 5
Cylinder 5
Piston 5
Crankcase 5
Crankshaft 5
Clutch 6
Flywheel 6
Ignition coil 6
Reduction gear 6
Instructions 7
Running-in 7-8
Starting 9-10
Technical advice 11
Clutch 11
Reduction gear 12
Ignition timing 13-14
Spark plug 15
Maintenance 16
Technical features 17
Ros 100 Light 17
Ros 125 Light 18
Contact 19
Introduction
Thank you for purchasing a ROS engine, developed and manufactured by Marcmotor.
The ROS 100 Light and ROS 125 Light are two-stroke internal combustion engines.
The torque and, thus, the power output of the engine are essentially determined by the
combustion process. Combustion, in turn, can be inuenced to a very large extent by the
ows and turbulences that can be produced in the combustion chamber by the geometry
of the transfer duct and the combustion chamber. The ows induced primarily by the in-
duction process and to a lesser extent by combustion-chamber geometry in conjunction
with the compression squish fold the ame front and thus accelerate the process of energy
conversion.Tumble, swirl andsquish increasewith engine speedand consequently,folding
of the ame front also becomes more pronounced. Those are the reasons that have urged
the ROSmotor and Marcmotor to deeply study the shape of the combustion camber, the
piston, the cylinder, the transfer duct, the transfer port, the crankcase and the crankshaft,
in order to obtain a very powerful engine with low consumption rate. Components already
available in other elds, like motorcycles and scooters, did not satisfy our target, that is
your target as well. We could have been content with spare parts already on the market,
but to be content is not enough for us. ROSmotor and Marcmotor have developed their
own parts. All these components are exclusively created for their engines: ROS 100 Light
and ROS 125 Light.They are all made in Italy and all the engines are manually assembled
by experts. Marcmotor is not a factory but, proudly, an Italian craftsman! Our saying is:
“Only innovation, not imitation”
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General advice
A scheduled and accurate maintenance programme allows you to get the best performances out of your
engine.That’s why we recommend you to follow the instructions given by this technical handbook.
This manual refers only to ROS 100 Light and ROS 125 Light.
For any further information, please contact us at the address and numbers you nd in the“Contact”section.
ATTENTION: This is not a certied engine! Use it only in applications where a sudden and unexpected
engine failure does not cause damages to things and people.
The data given in this manual may change and the manufacturer is not obliged to provide any updates.
Technical Handbook: Rev 1.0 – 2008
Component description
Head
The head is made of high quality aluminium alloy by shell casting, (shell is an exclusive
property of Ros motor). We developed the combustion camber to achieve good eciency.
Cylinder
Cylinders are made of high quality aluminium alloy by shell casting (shell is an exclusive
property of Ros motor). A high number of ns increase the surface area on which air can
act. This allows an optimal cooling. The transfer ports are designed to obtain high perfor-
mances in a wide range of rpm.
We have embodied the decompressor valve to get an easy start.
Piston
A high quality manufacturer produces the pistons upon our instructions. It is made of alu-
minium alloy with a single ring. It has a friction surface coated with a layer of molybde-
num disulde.
Crankcase
The crankcase is produced by earth casting. This technique allows to use a high quality
aluminium alloy. After casting, the crankcase is subjected to hardening treatment.
Crankshaft
The crankshaft is made of high quality steel. The producer provides for the balancing fol-
lowing our instructions, thus obtaining a very low vibration level.
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Clutch
TThe centrifugal clutch is adjustable, and it allows to transfer power at the right rpm.
Flywheel
The electronic ignition ywheel has an incorporated fan who generates a
forced air ow to cool down the engine.
Ignition coil
The ignition coil provides the power (volts) needed to spark the spark plugs from only 200
rpm and it is a variable timing unit until the maximum possible power and rpm.
Reduction gear
The helical gear runs in oil bath (40 cc of SAE 140 oil).
The gear ratio is 4:1.
Instructions
Running-in
All engines sold by Marcmotor are assembled by experts and, before being delivered, are
subject to a quality-check procedure. However, running-in is required.
A good running-in ensures long life to the engine and enhances performance of the me-
chanical components.
Before starting the engine, make sure that the carburetor has the right setup. To do this,
rst screw down the screw completely (look at Figure 1), and then unscrew it for 1+¼
turn. That way you can adjust the content of the mixture.
engine for emotion
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Running-in
Duration Carburetor Fuel mixture
30 liters 1+¼ turn of screw
from all closed
3%
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Remember that screwing in provides lean mixture, unscrewing gives rich mixture.
Prepare a 3% ratio mixture of fuel and synthetic two stroke oil.
Start the engine and warm it up on the ground.
Run it for no longer than 10 minutes, following this advice:
•Donotexceed4000rpm
•Donotmaintainconstantrpmforallthetime
•Ifyoufeeltheengineisloosingpower(asyoumayhavealean
mixture) adjust the carburetor settings according with the weather
conditions.
After this rst start, make a general check to ensure that everything is all
right and that there is no oil leaking out from the reduction unit.
For the rst 3 litres
•donotruntheengineatmaximumpowerandforalongtime
•oftenchangetheacceleratorandneverkeepthesamepositionfora
long time.
After this period:
•checkallscrews,bolts,nutsandmechanicalparts
•youcanprogressivelyincreasetherpmthattheenginereachesover4000rpm.
The running-in period nishes after 30 litres. Then, you can pass to the normal use:
Normal use
--- Carburetor Fuel mixture
--- 1 turn of screw from all closed 2,5%
Starting
Be careful when starting the engine!
Check the level of fuel in the tank.
Close the choke; see left picture of Figure 2.
For an easy start, when the engine is still cold, you need to press the inner membrane of the carburetor, but no longer than 2 seconds.
During this operation, you will see the fuel mixture owing into the carburetor.
Before pulling the rope handle, PUSH the decompressor valve (see Figure 3).
This reduces the strength you need to start the engine. It will automatically return to closed position when the engine starts.
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This engine has a variable ignition coil and the spark starts at only 200 rpm.
Give full-throttle, and at the same time pull the rope handle.
Warm up the engine for 3 minutes (progressively accelerating).
CAUTION! If the engine is already hot, never close the choke and never press the inner membrane of the carburetor.
Technical advice
Clutch
The engine is equipped with a two-shoe centrifugal type clutch. The centrifugal shoe is covered by brake lining (see
Figure 4).Two retaining springs are integrated in the shoe (see Figure 5).You can use these springs to set the rpm at
which the clutch starts to transfer power from the crankshaft to the reduction gear.
Any time you perform this operation, then you must lock the grub screw using Loctite 270.
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Reduction gear
The helical gear runs in oil bath (40cc of SAE 140oil).
The gear ratio is 4:1.
You can check the oil level by unscrewing the screw
that plugs the oil level hole (see Figure 7). Pay at-
tention not to damage the gasket. When you per-
form this operation, the engine or the reduction
unit must be placed on a horizontal and at sur-
face.The oil level is ne when it reaches the hole.
If the level is low, you must remove the oil cap and rell it with some new oil (see Figure 6).
To perform a total oil change, you must drain the old oil through the oil drain hole (see Figure 8). When the reduction
gear is completely empty, you can plug the oil drain hole with the screw. You must rell the gear through the oil cap
using a syringe with 40cc of SAE 140 oil. After this operation, you must check the oil level.
Ignition timing
The engine has a breakerless type ignition system. This kind of ignition is electronically controlled and provides the
power (volts) needed to spark the spark plugs from only 200 rpm and it is a variable timing unit.
To set the ignition timing, you can use a dial gauge to nd the top dead center (TDC), (see pictures on the left of
Figure 9). Remove the spark plug and screw down the comparator.
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Rotate the crankshaft and look at the comparator. During the compression stroke you see that the pointer of the dial gauge
rotates clockwise.
When the piston reaches theTDC, the pointer stops. If you continue to rotate the crankshaft, the pointer moves anticlockwise,
and indicates that the piston has passed theTDC. This way you can easily nd theTDC.
When you have found the TDC, you can mount the magneto ywheel.
The position of the ywheel is correct if the mark is aligned to the edge of the ignition coil (see picture on the right of Figure 9).
If the position corresponds to the one in the picture, you can tighten the ywheel nut.
The next step is to check the gap between the ywheel and the ignition coil. It must be of 0,4mm.To make an accurate setting
you must use a feeler gauge (see Figure 10).
Spark plug
We recommend you to use a NGK B10ES spark plug.
The spark tightening torque is 20 - 22 Nm.
You can also check the spark plug and“read the color”.
The condition of an engine can be judged by the appearance of the spark plug’s ring end. If the ring end of a spark plug is
brown or hazelnut color, the condition is good and the spark plug is functioning well. Dark brown
color indicates that you are using a too rich content mixture. Instead, a grey color indicates a too lean mixture.
Check the electrode gap and adjust again, if necessary, to 0,8mm (see Figure 11).
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Maintenance
Before and after
use
Every 25
hours
Every 100
hours
Breakups, leak of
oil, worn out parts
Check
Screws and nuts Check
Sliding throttle Check
Rubber bushing Check
Carburetor Check and clean
Reed valve Check
Power Unit:
- Spark-plug Replace
- Piston Clean soot
and measure
- Head Clean soot
- Head - O-ring head Replace
- Roller bearing Replace
Engine Block:
- Crankshaft
bearing
At 200 hours
replace
- Crankshaft At 200 hours
measure
- Crankcase seal Replace
Reduction gear:
- Oil Check level Change
- Oil seal Replace
- Bearings Replace
Technical features
Ros 100 light
Cycle Two strokes
Displacement 100cc
Bore 50 mm
Stroke 50 mm
Power 22 cv @ 10100 rpm
Compression ratio 11:1
Max rpm 10300 rpm
Thrust 65 kg @ 10100 rpm
Cooling Forced air
Piston aluminium with two piston ring S10 cromium plated
Cylinder Nikasil coated
Head aluminium G-Al Si 9 uni 3051
Cranckcase aluminium G-Al Si 9 uni 3051
Carburetor Walbro Wg8
Feeding Reed valve
Electronic ignition TCI
Spark plug NGK B10ES
Reduction with helical gear in oil bath
Reduction ratio 4:1
Clutch Centrifugal
Starter Manual
Fuel mixture of premium petrol 98 octane and 2,5% of synthetic High quality oil for two
stroke engines *
Consumption from 2.5 to 3.5 liters hours (it depends on load, speed and carburettor)
Rotations Clockwise; front of propeller viewed
Weight 10,5 kg
13,3 kg with muer and airbox
* For more details, read the“Running-in”section.
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Technical features
Ros 125 light
Cycle Two strokes
Displacement 125cc
Bore 54 mm
Stroke 54 mm
Power 29 cv @ 10050 rpm
Compression ratio 10,6:1
Max rpm 10250 rpm
Thrust 75 kg @ 10050 rpm
Cooling Forced air
Piston aluminium with one piston ring
Cylinder Nikasil coated
Head aluminium G-Al Si 9 uni 3051
Cranckcase aluminium G-Al Si 9 uni 3051
Carburetor Walbro Wg8
Feeding Reed valve
Electronic ignition TCI
Spark plug NGK B10ES
Reduction with helical gear in oil bath
Reduction ratio 4:1
Clutch Centrifugal
Starter Manual
Fuel mixture of premium petrol 98 octane and 2,5% of synthetic High quality oil for two
stroke engines *
Consumption from 2.5 to 3.5 liters hours (it depends on load, speed and carburettor)
Rotations Clockwise; front of propeller viewed
Weight 10,5 kg
13,3 kg with muer and airbox
* For more details, read the“Running-in”section.
Contact
For any further information, do not hesitate to contact us.
You can send your enquiries to:
e-mail: info@marcmotor.com
Phone and Fax: +39 0733 493158
Skype: marcmotor
Web: www.marcmotor.com
Marcmotor di Marcolini Gianluca
Via deiVelini, 293
62100 Macerata
Italia
PI - VAT: 01515340436
engine for emotion
ROS motor
LIGHT FLY ENGINES
engine for emotion
ROS motor
LIGHT FLY ENGINES
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