A penny between the gears won't work because that will only hold the outer clutch drum. You might be able to hold the clutch with a gloved hand and use an air impact wrench to spin the nut off. This is usually how I remove clutches.
A better way would be to remove the recoil stater from the left side of the engine and you will see a pulley bolted to the end of the crankshaft. This pulley will have notches in it that the recoil starter engages. Stick a large screwdriver or pry bar through two of these notches and then hold the end of the screwdriver or pry bar to keep the crankshaft from turning while you loosen the clutch nut. You will probably need someone to hold it while you remove the nut. Or you might be able to stick the screwdriver through the two notches and let the end of it catch on the frame or foot peg to keep it from turning. Once again, an air impact wrench will make this easier, but is not necessary if you hold the crankshaft like this.
Most 4-wheeler problems are caused by a loose nut connecting the handlebars and the seat!!
You only need two tools in life -- WD-40 and duct tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape.
Last edited by Helmut; 10-09-2011 at 04:12 PM.