Launched in 1927, the motorcycle featured a slanted 493cc overhead valve engine and a saddle tank that enabled a low seating position, improving the centre of gravity and handling.

[1] The first models featured a 493cc (80x98mm) single ported cylinder-head, topped by a cast-aluminium enclosure for the rockers, with exposed valve springs.

Easy cam contours and wide bases on the tappets ensured no associated valve clack, meaning that the Sloper was regarded by many as one of the smoothest and quietest of sporting 500cc machines.

[1] Early models had a duplex-frame and three-speed gearbox, but soon the top tube was replaced by an I-frame forging to support a new steering head.

[1] From 1930 there was an optional sporting kit for £10, including a high-compression piston, hardened valves and springs, and a racing sparkplug, but the company noted that there were few buyers.