[7] A European-styled version of the Manxman was shown in early 1962 at the Amsterdam International Auto Show and went on sale in April that year as the 650SS.
The air-cooled OHV vertical twin had been enlarged to 600 cc in September 1955 to satisfy the demands of the American market for larger engines.
(Anna J Dixon) A new alloy cylinder head was fitted that was derived from the 500 Domiracer that Tom Phillis had ridden to 3rd place in the 1961 Isle of Man TT Senior race, and achieved the first 100 mph (160 km/h) lap of the island on a pushrod machine.
The new head, twin carbs, sports camshaft and 8.9:1 Compression ratio enabled the engine to produce a claimed 52 bhp (39 kW) at 6,800 rpm.
[8] The combination of slimline featherbed frame and Roadholder forks used on the Dominators was carried forward to the Manxman.