Sunday, October 27, 2013

Secret Ninja 250 Carburetor Passages

Here are the secret passages in the carburetors. They are kind of hard to figure out sometimes and this picture guide shows where they are for cleaning purposes.

When cleaning your Ninja 250 carburetors, all of these passages need to be cleaned so that gas can get through them unobstructed. You can usually do this with spray carburetor cleaner. In some cases, a very thin copper wire can be used for stubborn clogs.

It is recommended that the diaphragms and plastic caps be removed prior to cleaning to prevent damage to the expensive rubber parts.

There are three jets in each carburetor - pilot, main and choke. The choke jet is pressed into the body and does not come out. The main jet is easy to remove with a socket and a large flat head screwdriver. It is actually two parts. The pilot jet is a little more difficult and requires a thin but strong flat head screwdriver.

On both the pilot and the main jet assembly, there are little holes in the ends and sides that must be clear. They are easy to miss sometimes so look carefully to find all of them.  The choke jet can be cleaned with a thin copper wire poked through the end followed by a squirt of carb cleaner.

 Carb Pilot jet Circuit

Carb Main Jet Circuit

Carb Fuel and Overflow Drain

Carb Diaphragm Intake, upper choke and vacuum ports

Carb Choke Circuit

Not pictured is the coasting enrichener circuit. It usually does not need to be cleaned, but because it contains a small diaphragm, you should be careful not to get carburetor cleaner inside it.