by EddieStone » Mon Dec 11, 2017 5:25 pm
The 'best' method for undoing the flywheel nut that I've used in an emergency without having access to a flywheel holding tool is a piece of rope.
A piece of rope about 6mm thick - tie a knot in the end and poke it down the spark plug hole. The knot jams against the piston and the head allowing you to undo the left handed flywheel nut. It doesn't damage either surface. You just need to be aware of where the piston is so the rope doesn't fall into a port. But it works well. In an emergency, I stress.
Works OK for doing the nut up as well.
I've always had a flywheel puller - they're cheap and small enough to fit in the toolbox compared to the flywheel holder - so I've never had to find a way of removing one without it. If I was really stuck, I'd consider loosening the nut and either running the engine (if it runs) or push starting the bike in gear to get the flywheel to spin and hope it loosens. You'd risk shearing the woodruff key and damaging the crank, keyway or flywheel, but it depends on what the alternative is!
You can get away without a holder, but realistically you need the puller.