ProFlow Main Jet Kits

Pro Flow Kits: Engineered With Excellence

Our Pro Flow Kits only contain jets with a linear relationship from one jet size to the next. Giving you predictable control over the air fuel ratio of your engine.

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Why use pro flow jets

Power Seamless Liquid Flow To Your Kart


Not Mass Produced

Exceptional Tolerances

Quality Control

Pro Flow Graph

Tuning made simple

Pro Flow Jet Kits

Have you ever changed the main jet in your carburetor and it didn’t produce the expected result? You are not alone. Many jets we have tested on our liquid main jet flow bench, are outside of what we have found to be the permissible tolerance in flow rate. For example, you may have 2 main jets, a 125 and a 128, the flow rate of the 2 can be so close that you cannot tell there is a difference in performance when you change from one to the other on your race weekend or test day.

This graph was created from real data recorded from our liquid flow bench. The flow rate of 9 different sizes and 14 jets per size was recorded. A total of 126 jets.

Each vertical series of data points are original Dellorto main jets of the same size. The series with the white graph line represents jets which have been selected with a linear relationship to complete a Pro Flow kit. The series with the red graph line represents one possible outcome when using or purchasing main jets which have not been verified on our liquid flow bench. 

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Factory Manufacturing - Tolerances & Quality Control Explained

Quality control is the process employed to verify that the finished product conforms to the manufacturing tolerances & specifications.

Manufacturing or Engineering Tolerance is defined as the permissible limit of variation in measured values. In regards to main jets, those values refer to material, surface finish, dimensions and flow rate.

The tolerances and quality control procedures employed in factory mass production have a large bearing on the parts accuracy and quality, which in turn impacts the cost. Decreased tolerances and rigorous quality control procedures equate to a higher degree of accuracy and increased cost. For the average consumer, non racing applications, the main jets sold by the manufacturers are of an acceptable tolerance and price point, but we run into problems when tuning the carburetor for high performance applications. If every main jet was to be made to an exact measurement, the price would be viewed as too high for the average consumer. For these reasons there is a variance in the flow rate of main jets which is not acceptable for go-kart racing applications. 

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The Pro Flow Solution

Our Pro Flow Kits contain jets with a linear relationship from one jet size to the next allowing you to have predictable control over the air fuel ratio of your engine.

Unparalleled Quality Control 

We flow test every jet that goes in each ProFlow Kit on our state-of-the-art liquid flow bench. The repeatability of the machine is verified 2 times for every 7 jets tested. If the verification is not met within 0.2% of the standard flow rate, all 7 jets are re-tested. This guarantees that what you purchase is what you receive.

Exceptional Tolerances

Our tolerance standards are based on liquid flow rate, and has been verified through dyno testing using an AFR sensor to ensure that your jets produce the desire results. Our standard change in flow rate from one main jet size to the next is 2.15%

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Pro Flow Solution

Pro Flow Jets Worldwide

 ProFlow main jet kits have been sold and shipped around the globe since 2016, to more than 16 countries. Not only that but they have won numerous races and Championships including the Rotax Max Grand Finals.

Unparalleled Quality Control


Exceptional Tolerance

Predictable Performance

Still Not sOLD?

The Pro Flow Guarantee

If you are not satisfied with your Pro Flow kit you can return it for refund within 30 days from the date you received it.
The client will be responsible for all shipping, duties, and taxes.
The cost of any jets which have been used or damaged will be deducted from the refund amount. 


Kit Selections

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Pro Series 100 – 110

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Pro Series 115 - 128

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Pro Series 122 – 135

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Standard Series Jet Kit 122 – 135

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Standard Series Custom Jet Kit

Custom 6

Pro Series Custom Jet Kit

Custom 11

Pro Series Custom Jet Kit

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Frequently Asked Questions

Why can’t I just measure my main jets with pin gauges instead of purchasing ProFlow jets?

Pin measurement is a great way to determine the hole size of your jets, but performance of a jet is affected by factors outside of that which can be measured by a pin set, such as inlet angle, outlet angle, surface finish, taper and roundness of the hole itself. The only way to accurately test the performance of a jet is to flow test it.

What happens if I lose one of my jets?

If you lose a main jet from your ProFlow kit, don’t worry. Every kit we sell has a unique serial number with your kit information. Contact us, provide your serial number, and we will match the flow rate of your lost jet.

Will ProFlow jets enhance my engine performance?

While ProFlow jets will not enhance the power output of your engine directly, they will save you valuable time and effort by eliminating the guesswork while tuning your carburetor. You will have peace of mind knowing that your main jets have all been verified and will produce the expected result when tuning.

The main jets that I need are not listed in your shop. Do you have any other sizes?

Please contact us for any other sizes or types of jet you require.

Should I do anything to protect my jets?

Yes. When not in use, keep your jets clean and sealed in their container. This will protect your jets from corrosion which will affect their performance. It is also important to use a proper screwdriver or main jet tool to prevent any damage to your jets. The main jet screwdriver tool can be found on our website. 

Are ProFlow jets interchangeable from one kit to the next?

Not all kits produced are with the same flow rate, therefore we do not recommend interchanging jets. If you would like to interchange jets please contact us with your serial number and we can provide you with the info you are looking for.

Are the main jets made at your shop or are they OEM?

The jets we test and use to create kits, available on our website, are OEM Dellorto 6mm and Dellorto 5mm.

Which engines do the jets fit?

The jets will fit any Dellorto carburetor which uses a 5mm or 6mm main jet. The 6mm jet is used in shifter kart, ROK GP, Super ROK using the VHSH 30mm carburetor. All Rotax Max EVO series using the VHSB 34 carburetor. The 5mm main jets are used in the mini & micro ROK classes with the PHBG 18mm carburetor.

Why is there 2 of the same size main jet in my Proflow Kit?

Many kits will have 2 of the same original factory size engraved on them. The first will have a lower flow rate than the next. Your jets are numbered 1, 2, 3, 4 etc and arranged from leanest to richest, from left to right.

Pro Flow Jets Support

Questions about what kit is right for you, contact us today

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