I wanted to ask my fellow Rotax owners if they or anyone they know have ever explored the possibility of substituting a pair of new Mikuni carburetors for the problematic Bing 64s on the Rotax 912 engine. I was looking at a Mikuni TM36-68 pumper carb on a guys 500cc motorcycle yesterday and it looked like a great set up. I took some rough dimensions and it looked like it could be made to work with some innovative massaging. The first question that comes to mind would be high altitude operation. I have used Mikuni's over the years in motorcycle operations and they have always been solid performers. I haven't checked hard dimensions yet to see if the 36mm would be the right one for the Rotax intake boot but Mikuni has many models in various sizes, so I'm pretty sure one that would fit and have the proper CFM flow for the Rotax. The Mukuni's sell for about $280. Here are some adaptability items that would have to be addressed:
Crossover tube adapability
Throttle cable adaptability
Choke cable adaptability
Intake & air filter boot adaptability etc.
Proper jetting.
Any thoughts from the community would be appreciated!