I pondered the same question some time ago, and ended up with dual 64's on my EA81 (same as Stratus, and Rotax 912/914). The 54 with that huge throat looks wonderful, and it is, on two strokes which has a pulsating in take, but with the constant suction of a four cylinder the slide in the 54 often sticks to its side wall, not closing when you want it to. . . The 64 on the other hand also has a slide, but it gets lifted by a vacuum imbalance (feed on demand) which helps a bit with altitude compensating, AND a butterfly in the throat to control the flow to the cylinder.
I hope this helps, and stay safe.
EA81 on a Q200 ZU-DWT
--- In AirSoob@yahoogroups.com, "meduster70" <meduster70@...> wrote:
> hello have a ea81 Subaru what size carbs work best for this? bing 54? 64 thanks Todd