Howarth was a motorcycle produced in 1931 by Whittaker Howarth.
Howarth, a firm Scott enthusiast had, a one time, been the manager of their Liverpool depot and had produced the Howarth silencer for the Scott. In 1931 he proposed to produce a three-cylinder, water-cooled, two-stroke engine with supercharger and desmodromic inlet-valves - this was a rarity indeed.
The engine, of simple construction in most respects, was 499cc. The cylinder block had exhaust ports on both sides, with poppet valves on the head, for inlet, opened by positive cams without springs. This was due to the need for the camshaft to run at engine speed to suit the two-stroke cycle. A vane-type, chain-driven Foxwell supercharger replaced the normal crankcase compression. This was mounted behind the cylinder block.
The engine, capable of 5,000rpm, drove via a four-speed gearbox and chain final-drive, and the whole unit was designed to be mounted in a conventional frame with girder forks.
Innovative though it was, the Depression was a bad time to launch such a design and the project came to nothing.