BMW’s R 18 cruiser isn’t just the biggest-engined motorcycle yet created by the German firm, it’s also a canvas for bike customisers to engage their wildest fantasies.

Anyone who watched the American Chopper reality TV series, and was spellbound by the outlandish two-wheeled creations of the Teutul father-and-son team, will understand the fascination of bespoke bikes and how many ways there are to re-imagine what is essentially two wheels, an engine and a petrol tank...