This app provides, using temperature, altitude, humidity, atmospheric pressure and your engine configuration, a recommendation about jetting for karts with Rotax 125 Max non-EVO (Micro Max, Mini Max, Junior Max, Max, Max DD2) engines, which use a Dellorto VHSB 34 QS/QD carbs.

This app can obtain automatically the position and altitude to get the temperature, pressure and humidity from the nearest weather station thought internet. Internal barometer is used on supported devices for better precision. Application can run without GPS, WiFi and internet, in this case user has to enter weather data manually.

• Two different tuning modes: "By regulations" and "Freestyle"!
• In first mode, the following values are given: main jet, spark plug, spark plug gap, needle type and position (including intermediate positions with washer), air screw position, idle screw position, optimal water temp, gear oil recommendation
• In second mode (Freestyle), the following values are given: main jet, spark plug, emulsion tube, needle, needle type and position (including intermediate positions with washer), venturi, idle jet (outer pilot jet), idle emulsifier (inner pilot jet), air screw position
• Fine tuning for all these values
• History of all your jetting setups
• Graphic display of fuel mix quality (Air/Flow Ratio or Lambda)
• Selectable fuel type (VP MS93, gasoline with or without ethanol)
• Adjustable fuel/oil ratio
• Adjustable floats height
• Mix wizard to get the perfect mix ratio (fuel calculator)
• Carburetor ice warning
• Possibility of use automatic weather data or a portable weather station.
• If you don't want to share your location, you can manually select any place in the world, jetting recommendation will be adapted for this place
• let you use different measure units: ºC y ºF for temperatures, meter and feet for altitude, liters, ml, gallons, oz for fuel, and mb, hPa, mmHg, inHg atm for pressures

The application contains four tabs, which are described next:

• Results: In this tab two jetting setups are shown. These data are calculated depending on the weather conditions and the engine and track configuration given in the next tabs.
This tab lets do a fine tuning adjustment for all values for each jetting setup to adapt to the concrete engine.
Besides this jetting information, the air density, density altitude, relative air density, SAE - dyno correction factor, station pressure, SAE - relative horsepower, oxygen pressure and volumetric content of oxygen are shown too.
You can also see in a graphic form the calculated ratio of air and fuel (lambda).

• History: This tab contains the history of all jetting setups. If you change the weather, or engine setup, or fine tuning, the new setup will be saved in history.

• Engine: You can configure in this screen the information about the engine, that is, engine model (Micro Max, Mini Max, Junior Max, Senior, Max DD2), needle type, float type and height, venturi (8.5 or 12.5), idle jet, idle emulsifier, fuel type, oil mix ratio and type of the track. Depending of this parameters, the jetting setups will be adapted.

• Weather: In this tab, you can set the values for current temperature, pressure, altitude and humidity.
Also this tab allows to use the GPS to get the current position and altitude, and connect to an external service to get the weather conditions of the nearest weather station.
In addition, this app can work with a pressure sensor built into the iPhone. You can see if it is available on your device and turn it on or off.

For Rotax Max EVO Engine please try our other app: Jetting Rotax Max Evo Kart.

If you have any doubt about using this App, please, contact us. We answer every question, and we take care of all comments from our users to try to improve our software. We are also users of this application.

What’s New

Version 1.9

• We have improved our weather calculator significantly. Now you can manually select which type of atmospheric pressure you are working with (for example if you use portable barometers, weather stations):
- sea level pressure QNH
- sea level pressure QFF
- station pressure (barometric pressure)
• Now, if you don’t want to see intermediate (half-steps) positions for the needle, you can turn it off on the 'Engine' tab
• New type of fuels have been added: VP Racing MS93 and 93 AKI with ethanol. Please check which fuel you are using
• On the results tab, click on the drop-down menu 'Weather (AirLab)', new data for tuners are available: Air Density, Relative Air Density, Density Altitude, Station Pressure, SAE - Dyno Correction Factor, SAE - Relative Horsepower, Volumetric Content Of Oxygen, Oxygen Pressure
• In the 'Results' tab, we added recommendations about spark plug gaps, positions for idle adjustment screw, optimal water temperature, gear oil recommendations
• Improved functionality and accuracy of fuel calculator
• Bug fixes for "share setup with friends" feature
• Added new type of spark plug: NGK Rotax
• Improved functionality for the feature 'Weather for custom location'. We added a search bar where you can enter the location name. Search places easier and faster now
• We reworked the altitude determination algorithm for the 'weather for custom location' feature. We hope that now, if you manually selected your location, the altitude will be calculated with much greater accuracy
• We added the ability to leave text notes for each history in 'History' tab. To do this, open any History, enter edit mode and add a note
• Now you can manually select the translation language. Application contains many special terms and sometimes translations that we offer are not always good. We are sorry. Now, if your phone (for example) in German, but you are unhappy with the translation you can switch to English (for example) only in this app (you don't have to change locale of device). You can find this feature on 'Engine' tab at the very bottom

Ratings and Reviews

4.9 out of 5
9 Ratings

9 Ratings

kz racer ,

Great app

Took some fiddling around as jetting needed to be skewed quite a bit to match my setup, otherwise jetting now is very very consistent, a lot less guessing and fooling around with the engine.

Richard Dybdah ,


Power feels great with base setups for my weather and location. Senior class.

Olly Waind ,

Big help

Simple and easy to use. Good for beginners.


49.2 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, Arabic, Catalan, Croatian, Czech, Danish, Dutch, Finnish, French, German, Greek, Hebrew, Hungarian, Indonesian, Italian, Japanese, Korean, Malay, Norwegian Bokmål, Polish, Portuguese, Romanian, Russian, Simplified Chinese, Slovak, Spanish, Swedish, Thai, Traditional Chinese, Turkish, Ukrainian, Vietnamese

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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