My question stemmed from looking at the apps (“Jetting Max Kart” and Rotax’s official “Rotax Max Jetting”). I have a Sr. Evo (used to have DD2 non-Evo, but not the concern here). I’m trying to learn.
With the same weather condition, why do the jet sizes from the 2 apps (supposedly both for Rotax Max Evo and non-Evo) vary greatly?
Today, as an example, Jetting Max Kart is calling for 162 while Rotax Max Jetting is calling for 126.
Both (Evo and non-Evo) are 125 cc, creating roughly the same HP. Stoichiometrically, they both should roughly require the same amount of fuel, regardless of the carb.
I know that Evo and non-Evo have different carbs, but why the jet size difference?