You pretty much have to have them on the motor because you won't be able to tighten the bottom clamps one the carbs are on. You can tighten the top clamps with a long screw driver once it is together. I lubed the boots and the carb with a thin layer of silicone plumbers grease. Then I set the carbs on the mounted boots and have a stern push. One side popped on the the other.When re-installing the carbs is it better to have the insulators on the carbs or the motor? Or maybe one side motor one side carb???