I use a chain wrench which I wrap around the flywheel and "jam" the handle against the frame. I got the chain wrench at Sears for $15. This keeps the flywheel from turning. Then a 1/2" drive xx mm socket with an 18" +/- breaker bar to remove the nut (reverse thread as you mentioned). Then use the flywheel remover. This has worked on both my KTM and Sachs motors.