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❑
Follow the previous procedures to fill the fuel tank and start the engine.
❑
Once the engine starts, keep the glow starter attached to the glow
plug and let the engine run for about 10 seconds without giving it throttle.
This will allow the engine to warm up. At this point the engine should be
running very "rich" and the engine will also sound like it's running rough.
❑
After the engine has been running for about 10 seconds, remove the glow starter from the glow plug. Advance the throttle in short,
quick bursts and drive the xT2 for about 2-3 minutes. If the engine is
running rich enough, you should notice smoke coming from the tuned
pipe and the engine should sound like it’s running very rough. Also, the
XT2 will barely be moving because the engine is running so rich that it
won't produce much power. This is what you want for now. If there is
not smoke coming from the tuned pipe, richen the high speed needle
valve 1/4 turn (turn counterclockwise). After 2-3 minutes stop the engine
by pinching the fuel line to the carburettor.
❑
Let the engine cool for approximately 10 minutes, then restart it.
Set the high speed needle valve mixture to a slightly leaner setting,
about 1/8 turn more in (turn clockwise). Repeat the procedure above, advancing the throttle in short, quick bursts and driving
the xT2 for about 2-3 minutes, then stop the engine again and let it cool for approximately 10 minutes.
❑
Repeat the procedure above, leaning the high speed needle valve
about 1/8 turn more each time. In all, you should run the engine a total
of about 45 minutes. After 45 minutes of run-time the engine will be
broken in. Run the engine with the high speed needle valve set slightly
rich, but lean enough to power the XT2 adequately. At this point the engine should hold a good setting on the high speed needle
valve and you can begin to fine tune the needle valve settings to increase performance.
The glow plug can make a big difference in how your engine performs. We recommend using a "hot" or "medium" heat-range glow
plug intended specifically for performance engines like the xTM Racing # 3
or the XTM Racing # 4 during the break-in process. After the break-in
period you may want to use a different heat-range glow plug. Do not use
glow plugs intended for four stroke airplane engines or glow plugs with
an "idle bar". Using the wrong type of glow plug will cause the engine
to run erratically and make it difficult to tune properly. The wrong type
of glow plug could also damage the engine.
gLoW pLug reCommenDation
air FiLter
The air filter is a very important part of your engine. Failure to use the air
filter will damage the engine in a very short period of time. Make sure that
you wet the air filter element and use a prefilter sleeve if you are driving
in dusty or wet conditions. See page 11 for more information.
To make sure that you're not leaning out
the engine too much and overheating it
during the break-in process, we suggest
using a temp gun to monitor the engine's
temperature.
During break-in, engine temperature
should not exceed 270ºF (132ºC). the
optimum engine operating temperature is
210º-230ºF (99º-110ºC). the minimum engine operating
temperature is 180ºF (82ºC).
engine breaK-in tip
Under no circumstances should you operate the engine without the air filter installed on the carburettor. The air filter
prevents dust and debris from entering the engine and damaging it. if you operate your engine at any time without the air
filter installed, the engine will be quickly damaged and require replacement of the piston and sleeve (liner).
step 1: breaKing in tHe engine
WARNING
Do not adjust the low speed needle valve until after the engine has been broken in. you can begin to adjust the low
speed needle valve after you have broken in the engine and after you have read and understood
step 2: Fine tuning the engine
on
the next page. The high speed needle valve is preset from the factory for easy starting in most conditions for the break-in period.
Break in the engine by running the xT2 on a flat surface
(car park/parking lot, etc.) without the body installed. It's
important that the engine receive adequate airflow during
the break-in process.
breaK-in tip
IMPORTANT
It is of the utmost importance that the engine never be leaned out too much. When running the engine, you should
always be able to see a slight trail of smoke coming from the tuned pipe. If you can’t, stop the engine immediately and richen the
high speed needle valve (turn counterclockwise). You should also make sure there is plenty of air flowing over the cylinder head
to keep the engine from overheating.
No two engines will have the exact same needle valve
settings once broken in. Different fuels used, different
types and heat-ranges of glow plugs, the outside air
temperature and air pressure all affect the engine. The
factory needle valve settings on page 12 are break-in
settings. If you reset the needle valves to the factory
settings, the engine will run very rich and you will need to
retune the engine.
tuning tip
During break-in, it's normal for excessive fuel oil and
exhaust residue to drip from the tuned pipe.
breaK-in tip
