3.Once you have cleaned out your engine, following the “tuning tip” above, place the vehicle on the ground and begin
driving it around while cycling the throttle between 1/4 and wide open, while you or your helper periodically check the
engine’s temperature and make adjustments to the Main needle (if necessary) during quick pit stops. We strongly
recommend doing this by running your vehicle in figure 8’s, in an area approximately 30’ x 50’. Figure 8’s, in this size
area, work good because they allow you to cycle the engine between 1/4 and full throttle without over-reving the
engine, while at the same time maintaining normal operating temperatures. Immediately, evaluate how the engine is
running. It should be running rich, meaning the engine should feel low on power and quite a bit of smoke should be
coming from the exhaust at full throttle. Break-in is a 4-tank procedure, and the goal during the first 4 tanks is to start
the Main needle (also known as the high-speed needle) at a rich setting. NOTE: a good starting point is
approximately 5/8 turn richer than the baseline Main needle setting found on page 17 of the manual. With each
consecutive tank, the Main needle should be leaned about an1/8 turn. As you lean the needle each tank, you should
notice that the engine’s temperature and performance will also increase. Once you are ready for the 5th tank of fuel,
ideally your Main needle should still be slightly on the rich side and within 1/8 to 1/4 turn from optimum setting.
Following these procedures, run the engine for a complete tank of fuel – then shut it down. Allow the engine to cool
down COMPLETELY before re-starting.
WARNING: During the break-in procedure NEVER allow the engine to over-rev to maximum RPM, as this will cause excess
stress on the piston, which can lead to the piston shattering. During break-in, when running at full throttle, always let off the
throttle before the engine reaches approximately 50% of its RPM potential.
NOTE: the low-speed needle will be fine-tuned later; however, during the break-in procedure it is a good idea to make sure it
is set about 1/4 turn richer than the baseline setting found on page 17 of the manual.
4.Continue this process for 4 tanks of fuel, making sure to allow the engine to cool down completely to ambient
temperature before running the next tank of fuel. Also, make sure to lean the Main needle 1/8 turn prior to starting the
engine each tank. On the 5th tank of fuel, you should be ready for fine-tuning the carburetor to optimal settings and
cool-down between tanks of fuel are no longer necessary.
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