Big enough for a quadbike.
Although originally designed for mobility scooters, the Hideyhood 90º is perfect for all manner of uses. It’s easily big enough for 5 full size bikes, more if you “top to tail” them. 2.5 metres wide, 1.67 high and the same depth. Takes minutes to erect, fixes to walls, sheds or fences, as long as they’re over 1.15 metres high. Plenty big enough for a moped, scooter or smaller motorbikes.
The Hideyhood 90º is even big enough for a quadbike. 
Here’s one with a Polaris Trail Boss 330 inside (just!).