Honda CT90 - turn signals Turn signals became a standard fixture on the CT90s in 1973 following the introduction of federal legislation in the USA that made them mandatory on all cars and motorcycles. Retrofitting them to older bikes is straightforward... Turn signals became a standard fixture on the CT90s in 1973 following the introduction of federal legislation in the USA that made them mandatory on all cars and motorcycles. Retrofitting them to older bikes is straightforward... Nick Honda CT90