I know people that put a piece of wood in front of the sprocket that the front sprocket jams up against or a 2x4 through the front part of the rear wheel. Rotate rear wheel until it is trapped against the swingarm. I was lucky and my impact whacked on it a little and it spun off. I know someone else who took a winch strap and strapped their rear tire to the lift so it wouldn't move. If you don't have a lift, strap it to something else.
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