Do You Need To Rejet A Fuel Injected Bike?

by | Last updated on January 24, 2024

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Absolutely! When you change your intake (adding a free flowing intake or filter) you will need to add a Fuel Processor to your fuel injection or re-jet your carburetor.

What is Rejetting a motorcycle?

The holes regulate the amount of fuel that goes through the carburetor. Bigger jets allow more fuel and smaller jets allow less. The rejetting process

figures out which size jets is needed to keep an engine running with the right mixture

. Too little fuel and the engine may starve or overheat at high RPMs.

Do I need to Rejet with a slip on exhaust?

Do You Need To Rejet With A Slip On Exhaust? In all cases, though,

you don’t need to rejet with a put slip on

, but you will need to adjust your a/f screw with it in order to get to your carb easily.

Do I need a power commander with a full exhaust?


the only time you need mapping (power commander) is if you do anything to change the air/fuel ratio

. the reason a slip-on does not need a power commander is because the exup valve (a servo controlled butterfly valve in your exhaust) is still in place and it manages exhaust flow and back pressure.

How hard is it to Rejet a carburetor?

Rejetting your carburetor can be a pain if you can’t seem to get the right size jets. But it’s definitely

not a very difficult procedure

and it can really help the performance of your motorcycle.

How do I upgrade my motorcycle carburetor?

How do you Rejet a motorcycle carburetor?

Does a slip on exhaust increase horsepower?

Slip-on mufflers

won’t improve horsepower or performance

. Slip-ons are mostly for decoration and noise enhancement. Installation on some bikes may require bodywork done by a professional at a shop.

What is the difference between slip on exhaust and full exhaust?

There are two types of aftermarket exhausts.

A “slip-on” replaces only the muffler, while a “full system” replaces everything: header, midpipe and can

.

What happens if pilot jet is too big?

Typical Lean Conditions:

(A too-large main jet also mimics this symptom.) –

The engine runs hot, knocks, pings and overheats

. – The engine surges or hunts when cruising at part-throttle. – Popping or spitting through the carb occurs when the throttle is opened.

How do you Upjet a carburetor?

Are carburetor jets universal?


Yes you can

. As long as they are the same style of Keihin jets.

How much HP will a Power Commander add?

The Power Commander is a tuning tool to adjust fuel, and on some models ignition timing. Just adding a Power Commander to a completely stock vehicle

usually does not increase peak horsepower

. It usually will improve drivability, throttle response, and mid-range horsepower and torque.

Do you need a tune after exhaust?


No you will not need a tune if you get an exhaust

.

Does a Power Commander make a big difference?

this smooths out your power curve making power delivery better while gaining a few HP throughout the rev range, so in terms of making your bike run better, especially with an aftermarket slip on & filter, then

yes it does make a difference

.

How do I know what jets to put in my carb?

How do I know if my pilot jet is too small?


If you have your fuel screw less than 1/2 turn open from fully closed

, that means your pilot circuit is too rich, and you should go to a smaller pilot jet. If you have your fuel screw open more than 2-1/2 to 3 turns, your pilot circuit is too lean, and you need to go up a size on your pilot jet.

What does jetted mean on motorcycles?

Jetted means that

a jet kit has been installed

. Which in turn means the jets in the carbs have been change so that the appropriate air:fuel mixture is achieved and thus maximum performance. Keep in mind, if it wasn’t done correctly then the bike will not reach maximum performance.

Are motorcycle carburetors interchangeable?


You’ll have to ensure the draft is the same

(side-draft carb replaced with a side-draft carb, etc). You could put a down draft carb in place of a side-draft, but it would necessitate some unwanted plumbing, pure ugliness at the carb location, as well as a probable loss of performance.

Are carburetors interchangeable?

Answer: The most common answer is that is

has to be tuned to match your engine

. Rarely will a new carburetor work right out of the box and some tuning will be required. The adjustment method can differ with the carburetor type, but the general progression is the same.

Do carburetors add horsepower?


A bigger carburetor has a bigger space that can help to increase horsepower

by allowing more air and fuel to travel into the combustion chamber at once. More air and fuel in the combustion chamber means bigger combustion is generated. Thus, more horsepower.

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

Q: How Do You Tell if a Carburetor Is Rich or Lean? A: One way to tell for sure is by “reading” the spark plugs.

If the plug tip is white, the mixture is lean. If it’s brown or black, it’s rich

.

How do you Rejet carbs for pod filters?

What does the pilot jet do in a carburetor?

The pilot jet

handles the mixture from idle to 15 to 20 percent throttle

. Air comes in through the front of the carburetor drawing fuel up through the pilot with a vacuum that is created as the air flows through the pilot circuit.

Is a full system louder than a slip-on?

Registered.

The full system will always be louder

. the reason for this is that the stock systems almost always use bigger diameter pipes. The reason for this is that the stock mufflers are typically required to keep noise levels down.

Do slip ons make bike louder?

1. Sound Improvement. Aftermarket slip-on exhausts are absolutely great if you want a louder and more aggressive sounding motorcycle. Generally speaking,

the smaller and more hollow the slip-on exhaust is, the louder your motorcycle will become

.

How much HP does a Two Brothers exhaust add?

Obviously, installing the full exhaust system will bring more power, but both options have been proven to significantly increase horsepower and torque. In a test performed by Cycle World, “Compared to the stock setup, [Two Brothers V.A.L.E Exhaust] output improved from 2500 RPM to redline, with gains of

8 HP

and 7 ft.

David Evans
Author
David Evans
David is a seasoned automotive enthusiast. He is a graduate of Mechanical Engineering and has a passion for all things related to cars and vehicles. With his extensive knowledge of cars and other vehicles, David is an authority in the industry.