As a further explanation, depending on what kind of motorcycle you have, you would need to go into the "config" notecard inside the motorcycle and adjust the sensitivity. One I had was set to "10" and left/right would send me off the road. I set it to "3" and it was nice and easy adjusting straightaways, but then full turns are a bit tougher.
Note that the motorcycle may show as "no mod" in inventory/rezzed, but for at least some motorcycles the config notecard is editable. Make a backup of the notecard contents just in case.