Yup, it's a carb.
But with a flat slide.
All kidding aside it changes the way fuel is processed, causes more of a two stroke feel in my opinion instead of smooth power. I didn't like the one on the 450 I had though.
This is my trike. There are many like it but this one is mine. My trike is my best friend, and it is my life. I must master it as I must master myself. My trike without me is useless. Without my trike, I am useless. I must ride my trike true. My trike and I know that what counts is not the amount of miles we ride, but the time we ride together. My trike is human in it's own ways, therefore I will learn it as my brother. I will learn it's weaknesses, it's strengths, it's parts, and it's soul.