Scott (Six Starved) taught me a exceptionally clever way: Remove one plug and stuff a length of nylon rope into the cylinder. Leave a tail hanging out. Slowly rotate the motor over until the engine locks up and the bolt will loosen. Remove the bolt and the washer and re-install just the bolt - but only a few turns. Install your balncer puller and rotate the motor the opposite way far enough that you can pull out the rope.