By Ian Falloon. The essential book for owners and would-be owners of the BMW`s classic boxer. Full description of the model`s development, analysis of the boxer twin engine. Detailed look at the R90S and R100RS, its racing history, year-by-year revisions to each model during the whole production run, all engine and frame numbers by year, technical appraisal and a complete appendices of technical specifications. Hardback, 160 Pages, Size: 210 x 250mm. Book is new and unread