Advanced design for the era was let down by shoddy materials, naff chassis and dubious braking. However, those left on the road have more or less been fixed and used mildly has its uses as an unusual commuter. Go for post ’60 bikes as they dumped the massive rear enclosure. Most engines rattle and leak oil, avoid those with knocks. Can be upgraded with other Norton suspension and brakes. Some well sorted bikes out there.