I had the speedo-cable pop off my Ninja 500 once. Didn’t know what was wrong until I pulled into my driveway and heard something dragging under the bike. Just be sure that it is secured in place under the gauge cluster there. If it pops off again, it could get caught in the wheels, and then you’ll have serious problems. You may want to consider using some loctite to make sure that it absolutely doesn’t come off again.