MCD Racing RR5 Competition, Instruction Manual

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11
Caution!
The mixture gets too rich if too much fuel enters the crankcase or the choke stays closed for too long. This
causes the engine to stall. In this condition, the pull-start can only be operated with considerable force. Do not
try to start the engine, but rather drain the excess fuel to prevent damage on the engine or the pullstart
mechanism. Proceed as outlined below:
- Take out the spark plug and let the electrode dry
- Fully open the choke
- Pull the starter cord several times. CAUTION: fuel may spatter from the combustion chamber and catch fire,
and if contacted irritate your eyes and skin.
- Reassemble the spark plug.
- Start the engine again.
- Pulling the pull-start cord to its full length can damage the pull starter.
- Pull about 50-60cm of the cord. (first try slowly with the ignition disengaged)
- Never apply too much force to the pull-start mechanism.
Caution!
Caution!
Setting the idle-mixture needle L
Setting the mixture-needle H for WOT
- Let the engine warm up.
- If the engine responds weak when throttle is pulled , the idle-mixture is too lean.
- Richen the mixture as you slowly turn the idle-mixture needle counter-clockwise by 5 min increments.
(As indicated in Figure O on the previous page)
- If the engine responds to throttle input with stuttering and smoke plumes from the exhaust, the
idle-mixture is too rich.
- Lean the mixture as you slowly turn the idle-mixture needle clockwise by 5 min increments.
- Prop the car and let the warmed up engine run at full throttle for a short duration.
- Lean the mixture as you slowly turn the mixture needle H clockwise by 5 min increments.
- Richen the mixture as you slowly turn the mixture needle H counter-clockwise by 5 min increments.
- We recommend a setting slightly on the rich side to prolong the engine life.
The mixture must not be set too lean under any circumstances! Engine lubrication solely depends on the oil contained in
the fuel. Too little fuel in the mixture leads to overheating and piston squeezing due to lack of lubrication. During operati-
on, a lightly blue smoke trail should be visible. Otherwise, immediately stop the engine and richen the mixture accordingly.
Also make sure that the cylinder is cooled enough with fresh air to avoid overheating. Spark plugs are subject to wear,
especially during break in. Always keep spare plugs of the CMR 7H class at hand. An unsuitable spark plug will make the
engine run rough and hamper carburetor settings. Check spark plugs for visual defects and proper electrode clearance.
Break-in procedure
Toe Setting
The engine performs best after a short break-in period due to the engines internal parts manufacturing methods. During
thisbreak-in, the piston’s and liner’s surfaces mate each other for best performance and best break-in possible. Break in
the engine by driving for around 1tank of fuel before full throttle may be applied.
Toe-in:
Mount the toe inserts pointing the direction that the hubs will be installed
(L or R) as shown beside.
e.g. If the hub will be installed on the left side, the inserts should be pointing L
for toe-in.
Toe-out:
Though not used frequently if toe-out desired in the rear, simply swap left and
right hubs. You will obtain same amount of toe-out.
The toe angle can be changed by replacing the inserts with the desired angle.
The degree which defines the toe-angle can be noticed by the sign on the
inserts as indicated in the figure below.
Hub
Toe inserts angle
Toe inserts pointing left
0° 1° 2° 3°