This happened to me too. Check the top center tab in the "upper rear cover" (page 3-4 in the service manual, if you have one). The upper rear cover has the word YAMAHA painted on it. This cover has a tab in the center, it slides into a slot in the grab bar assembly. When I put it back together, I had the tab below the slot, and the left side of the cover kept popping out. Put the tab in the slot and you'll be good to go.
Ride safe,
Larry
Ride safe,
Larry