Removing magneto and stator?

I have to take apart a 700 Yamaha Triple and need to know how to remove the magneto from crankshaft. Do I need a gear puller? I see that it has a key, but how would you get a puller in the case housing to grab it and pull it off the shaft?

you need a flywheel puller

what size is the magneton puller on srx 700