1. You can remove the guide rail pin with a home-made puller. A bolt threaded into the pin with a nut/washer/socket set-up works well. I've done it hundreds of times. I've used the tool by Hazett? as well. 2. Remove only the exhaust sprocket. The intake sprocket includes the cam advance mechanism and there's no need to mess with it. 3. Yes, the chain will fall off the crank gear, but don't sweat it. It's easy to put back on. I've seen some guys hold the chain tight when removing the cam sprocket and then wire tying it to the tensioning rail to keep it on the crank. Either way, it's up to you. 4. I forget the size. I just know it's the BIG one in my socket drawer, sorry. Good luck and let me know how it goes.