Why?

["Peter Svilans" <peter.svilans@rogers.com>]

Hello Jack:  From "The Restoration of Vintage & Thoroughbred Motorcycles":

" It is customary to have one complete circular bend (preferably in the
horizontal plane) in a petrol pipe or long oil pipe to give a certain amount
of resilience.  Without this the pipe would eventually fracture, as copper
tends to work harden as it ages."

Best regards
Peter