BASICS OF CARBURETOR OPERATION
The basic secret of carb function is that inside each carb are
thousands of tiny gnomes; each with a small bucket. As you open the throttle,
more of these gnomes are allowed out of their house and into the float bowl,
where they fill the buckets and climb up the carb's passages to the intake,
where they empty their buckets into the air stream.
But, if you don't ride the bike for a while, bad things can
happen. Tiny bats take up residence in the chambers of the carb, and before
long the passages are plugged up with guano. This creates a gnome traffic jam,
and so not enough bucketfuls of fuel can get to the engine. If it gets bad
enough, the gnomes simply give up and go take a nap. The engine won't run at
all at this point. Sometimes you'll have a single dedicated gnome still on the
job, which is why the bike will occasionally fire as the gnome tosses his lone
bucket load down the intake.
There has been some research into using tiny dwarves in modern
carbs. The advantage is that unlike gnomes, dwarves are miners and can often
re-open a clogged passage. Unfortunately, dwarves have a natural fear of
earthquakes, as any miner should. In recent tests, the engine vibrations caused
the dwarves to evacuate the Harley Davidson test vehicle and make a beeline for
the nearest BMW dealership. Sadly, BMW's are fuel injected and so the poor
dwarves met an unfortunate end in the rollers of a Bosch fuel pump. Other carb problems can also occur. If the level of fuel in the
float bowl rises too high, it will wipe out the Section 8 gnome housing in the
lower parts of the carb. The more affluent gnomes build their homes in the
diaphragm chamber, and so are unaffected. This is why the bike is said to be "running
rich".
If the fuel bowl level drops, then the gnomes have to walk
farther to get a bucketful of fuel. This means less fuel gets to the engine.
Because the gnomes get quite a workout from this additional distance, this
condition is known as "running lean". The use of the device known only as the 'choke' has finally been
banned by PETG (People for the Ethical Treatment of Gnomes) and replaced by a
new carb circuit that simply allows more gnomes to carry fuel at once when the
engine needs to start or warm up. In the interests of decorum, I prefer not to
explain how the 'choke' operated. You would rather not know anyway.
So, that's how a carburetor works. You may wish to join us here
next week for electricity 101, or "How your bike creates cold fusion
inside the stator, and why the government doesn't want you to know about it."
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