A complete kit with jets for the Dellorto carburetor on a Rotax Max Engine.
The jets on a carburetor regulates how much gasoline an engine gets
A general rule is that the colder and oxygen richer the air, the engine needs more gasoline and the hotter it needs less gasoline.
Here are some standard recommendations
Rotax Max Junior / Senior Evo
18 degrees and warmer nozzle 122
Cooler than 18 degrees nozzle 125
Cooler than 10 degrees 128
Our experience is that there is hardly any difference in jets between Rotax Max Junior and Rotax Max Senior.
Rotax Max DD2 Evo
18 degrees and hotter nozzle 130
Cooler than 18 degrees nozzle 132
Cooler than 10 degrees 135
The effect of the needle
You can adjust the response slightly by raising and lowering the needle position, ie the throttle needle that goes down in the jet.
The higher the needle you have, the more gasoline it gets at the throttle and the lower the needle the less gasoline. What may be a little confusing here is that position 1 on the clip to the needle gives less gasoline and position 5 on the needle gives more gasoline.
Once you find the right jet, this is where we work most to fine-tune the character of the engine.
Rotax has an App for Android and Iphone that helps you find the right setting. The app should be taken as a recommendation and then you should experiment yourself to find the right feeling for you.
Iphone:
https://apps.apple.com/se/app/rotax-max-jetting-guide/id1152315347
Android:
https://play.google.com/store/apps/details?id=com.carburetorjetting.calculator&hl=en_US