Ariel Square Four - Sectioned Engine | Jeff | Flickr
NO 55: CLASSIC ARIEL SQUARE FOUR MOTORCYCLE ENGINE | Flickr
59 Ariel Square Four Photos and Premium High Res Pictures - Getty Images
Ariel Square four engine. I think this is one of the later ones which had improved cooling of the rear cylinders | Sketches, Motorcycle engine, Scooter bike
Ariel Square Four MK1 1949-53 exploded engine view with part numbers 9.5 x 14" | eBay