On a sandy beach I would bury a layer or two of plywood just below the surface of the sand and then smooth it out after placing the bike. In this case the beach had a hard area that was not sandy at all. Being hard and dry the bike could stand on its own.
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I was pretty happy with the end result. When things were set and I liked where the sun was, creating a good shadow. Adding in some additional light to fill in the rest of the shot and it came together as I had imagined.
Orcatek Automotive and Motorcycle Photography - Phoenix, Arizona