Which Main Jets Are On A Rochester Carburetor?

What Jets are in carburetor?

On the bottom for the carburetor you typically have two jets. The pilot, the smaller of the two, and the main jet. Let’s start with the pilot. The pilot jet handles the mixture from idle to 15 to 20 percent throttle.

Where is the main jet on a carburetor?

The main jet is located at the bottom of the carburetor inside the float bowl. It’s the larger of the two jets, and it is installed in the needle jet—that part we will be covering next week. If this guy is plugged up, you’re in for a full carb cleaning ritual.

How do I identify a Rochester 2 jet carburetor?

All Rochester carburetors are identified by a seven- or eight-digit part number. The earliest units, made before mid-1968, had a triangular metal tag attached to the fuel bowl. The seven-digit part number is listed on the tag. You occasionally find original carburetors with an anodized tag of various colors.

How do you tell if a carburetor is rich or lean?

Typical symptoms of a rich mixture are:

  1. Poor fuel economy.
  2. Sluggish acceleration.
  3. Choke not needed from cold starts.
  4. Sooty or black spark plugs.
  5. Sooty or black muffler end pipes.
  6. Strong smell of gasoline when the machine is at idle.
  7. Uneven running (will often slow from regular idle rpms and then stop)
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Can you drill out carb jets?

By drilling out your stock main jet to larger sizes you will be able to narrow down what jet size your carburetor needs. You will need a numbered drill bit set. If it’s lean and you need to increase the size of your main jet, drill the jet out with the next size larger drill bit, which in this case is the #60 bit.

Are all carb jets the same?

Yeah, most Keihin jets are interchangeable and most Mikuni jets are interchangeable (though the two brands are not interchangeable with eachother). Any motorcycle dealer should be able to get jets for your bike even if they do not sell the brand of bike you have.

What happens if main jet is too big?

For example, using too large of a main jet will cause more fuel to enter the combustion chamber than it can efficiently burn. This will result in a “sputter” at full throttle. It could best be described as a rapid misfire.

Are Quadrajet carburetors any good?

The truth is, a properly tuned Quadrajet can be just as efficient and reliable as a bolt-on substitute performance carburetor. The Quadrajet has many model designations; the most adaptable units were designated as 4M, 4MC and 4MV, and most were rated at 750cfm until 1972 when their rating was increased to 800cfm.

How do I know what Rochester carburetor I have?

All Rochester Quadrajet carburetors are identified by a seven- or eight-digit GM part number. On units made before mid-1968, the part number was stamped around the outside edge of a round metal tag attached to the fuel bowl.

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How many CFM is a Rochester 2 jet?

Carb Sizes and CFM The cfm (cubic feet per minute-a measure of how much air the carburetor can flow) on the Rochester 2G ranges from about 225 cfm in the smallest applications up to what Rochester calls a 435 cfm.

What is a Rochester carburetor?

They are 2G, 2GC and 2GV. 2G simply means that it is a two bore carburetor. Typically the Rochester 2 barrel carburetor is used on V-8 engines where each bore supplies air and fuel to 4 cylinders through a divided intake manifold. Two different throttle body flanges are used on the 2G carburetor, 1 1/4″ & 1 1/2″.

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