you may need a puller to get the rotor off
SLP in idaho makes a great aftermarket rotor
i shaves off weight and stops great
1lb of rotating mass is = to 7 pounds dead stationary weight
no real tricks to doing it just take your time and have a beer
check the chain and sprockets real well while your in there
for cracks or wear
if its a 800 mountain sled you may want to think about dropping a
tooth on the top sprocket
hope this helps