1991 Polaris Indy 500 Clutch Removal???

[HULKAMANIA]

Hey guys Im working on my 91 Indy 500 and I just am not sure how to get the clutch assembly apart, and off the shaft of the engine. I guess it would be called the clutch, its where the cog belt attaches but as far as the technical term Im not sure, I havent been around snowmobiles much at all. Do I have to have a puller to get this off? Also do any of you guys know how hard it is to do an oil injection block off and just run the premix in the tank? Why cant you just plug the line of the tank, and disconnect the throttle cable that runs the injection? I am just wondering.