Carb or RAVE rebuild first

[Lakedweller]

1998 challenger 1800 2 rotax 787. At mid throttle there is a difference in throttle position to sync the engines. Same rpm at idle and WOT. The starboard engine takes a bit longer to spoil up too. Do I rebuild carbs or RAVE valves first

 

[2x2smoke]

i would do compression test first and compare the plugs

then clean /inspect the rave valves