Harley-Davidson XA Into the war, the government asked Harley to build a bike that was similar to the BMWs used by the Germans. So they didâto exacting specification. The 740cc flat twin and shaft drive aped the R71 perfectly. Harley built 1,000 XAs and even used the platform to test its first telescoping fork.
Definition of atom for English Language Learners. : 1  the smallest particle of a substance that can exist by itself or be combined with other atoms to form a molecule. : 2  a very small amount of something.
electron. any of the negatively charged particles arranged in orbitals around the nucleus of an atom and determining all of the atom's physical and chemical properties except mass and radioactivity.lectron. any of the negatively charged particles arranged in orbitals around the nucleus of an atom and determining all of the atom's physical and chemical properties except mass and radioactivity.