The flywheel nut is usually easy to remove with an open end wrench. A sharp blow with a heavy hammer will knock it loose as the inertia of the heavy flywheel will keep it from turning. A "crows foot" socket at a 90 degree angle to the left (So pulling on the torque wrench will hold it against the nut) and a strap wrench will let you torque the nut to the required 75 the 80 Foot Pounds.
Bouncing the flywheel back and fourth with the starter rope against compression gives you a flying start when you crank the opposed twins and makes the Speeditwin much easier to start than the Speedifour (without a compression release) or Big Four. (Stacked Speeditwins) . . . 😀
