Tachometer:

There are people who feel that every moped and motor scooter should be fitted with a tachometer (rev counter) as standard. There are others who find it a dodgy instrument since it tends to distract the rider’s attention from the road. If you belong to the first category and have a scooter or moped without a rev counter, this article is for you. It describes a straightforward design of such an instrument that can be fitted to any model of moped or scooter.