i would assume you have cranks with a built in sprocket, if this is the case, you can't
I'm assuming that by "front sprocket" you are referring the gears attached to the crankarms, referred to as "chainrings". If you are removing the outer two rings, use a 5mm allen wrench to remove the four chainring bolts attaching the rings to the crank. To remove the inner ring, you will have to remove the crank from the bottom bracket, a process requiring a specialized tool known as a "crank puller". For either of these processes, though, consider consulting your local bike shop to make sure you are taking the correct approach and not damaging or degrading your bike.
After you remove everything required to get to it, it takes a special tool to pull it off the crankshaft.
The sprocket on the nose of the crankshaft that drives the cam sprocket.
It runs off of the front of the crankshaft, under the crank sprocket and crank pulley. You have to to remove the timing chain/belt.
should be an Allen head or torx screw in the center of the crank.
If the crank has 48 and the sprocket 12 then 48/12=4. The wheel will turn 4 times for each turn of the crank.
Chain is on the smallest sprocket on the crank and on the largest sprocket on the rear wheel
you must remove the clutch hub (along with clutch plates etc) which will require a speciall puller...also, remove the front sprocket 9on the end of the motor crank), once they are both removed (the belt and all) you will have access to the bearing...
Look closly at the sprocket and you will see a small dot or indentation,you align both dots (cam and crank sprocket dots)
20 rpm
Use a dental pick or similar tool and carefully pry off center cap to reveal Allen screw.
Pop back the plastic cover from the center of the crank and remove Allen or Philips screw. Handle will then pull off.