Just wanted to add a couple more paragraphs from the article linked above.
This, and the paragraphs above, seems to suggest that the neutral time during a turn would be that portion of time when speed and turn radius are constant. If speed or turn radius changes then rider input is necessary to maintain lean and line and / or vice versa. Most riders, especially racers, will slow on approach and entering of a turn, then accelerate out of the turn, so neutral time would be minimal.
Excerpt from How To Steer a Motorcycle, Articles by Paul
,,,,,,,,,,,,,,And what about gyroscopic forces? They increase with wheel and engine speed. They are almost nil at walking speed, but if you have heavy wheels, like the cast aluminum mags on late-'70's Yamahas, they have a significant effect at 60MPH. Their overall effect, if you don't turn the handlebars, is to resist changing the lean of the motorcycle. Keep in mind, though, that only the front wheel's gyroscopic forces will make the motorcycle lean, since that is the one that you can turn to the side. There are also gyroscopic forces present in more parts of the motorcycle than just the front wheel. I just went out to my garage and took a motorcycle wheel, spun it on its axle, held it, and turned it different directions. Here are the results:
Regarding front wheel motion I have these observations. If you steer it left, it leans right. If you steer it right, it leans left. But it only leans farther as long as you steer farther. If you hold your steering angle, it holds its lean. If you steer straight again, it goes vertical. So the gyroscopic force has the same effect on lean as countersteering, but that force disappears as soon as you stop moving the handlebars, and reverses as you bring them back to center. This means that in that initial stage when you get the bike leaned over, gyroscopic force works for you in the front wheel, but as soon as you try to steer around the corner, it works against you, tending to stand the bike up. Obviously, we overcome that standing up force, because we can stay leaned.