How a Carb Works

[Sidecar Bob]

Having a more in-depth understanding of the basics of carb design and function will likely make it far easier to get them set up correctly.

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 drive 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 gnome housing in the lower parts of the carb. The more affluent gnomes build their homes in the slide 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."

[the chef]

Love your posts man , keep them coming !!! Thanks alot for them all ! the chef

[octane]

Hi Sidecar Bob

Oi...am I glad that you are here!
Please keep up the good work!

Best regards

Sidecar Octane
ha ha , well I was, back in the late seventies:

Can you guess what kind'a bike it is?

[Sidecar Bob]

[quote="octane"]Can you guess what kind'a bike it is?[quote]
I'm no expert on postwar German bikes, but it looks like an R25 BMW or something along those lines. And I think the sidecar is a Stieb.

[octane]

naaaaaaaa.

It's a Danish NIMBUS inline four 750cc bike
Here's a page in English on the Nimbus.
On the sidecar you're right and not; it's a Danish made Steib copy called Bender.

Best regards
Octane