Photo ou archives : M. Woollett
7315
GRINDLAY PEERLESS
1000cc JAP - 1929
Peerless performer
The Grindlay firm from Coventry initially built sidecars. But in 1923, it began producing motorcycles. The first models were powered, somewhat originally, by Barr & Stroud sleeve-valve engines, initially in 998cc form, then in capacities of 350 and 500cc.
From Sleeves to Poppets
In 1927, Grindlay Peerless (the "Peerless" adjective had been added for the production of bikes) abandoned the Barr & Stroud units in favor of more conventional JAP engines.
Special Crankshaft
In order to publicize its products, the firm signed Bill Lacey, a talented rider and tuner who lived close to the Brooklands track. The first Grindlay Peerless developed by Lacey achieved an important success in 1928: It broke the 500cc hour world record, covering 103.3 miles in 60 minutes. Lacey immediately decided to build a record-breaking machine powered by a 1000cc JAP engine. As with all the machines built by Lacey – he later prepared the Manx Norton with which Mike Hailwood achieved fame in the 1950s – the engine was considerably modified. Lacey made a special crankshaft supported in two enormous roller bearings – four-row on the transmission side, three-row on the camshaft side. Special Martlett pistons raised the compression ratio to 10:1 and the ignition used two spark plugs per cylinder. Lacey failed in his bid with this machine to break the world speed record, but he set a new 100 miles record at an average of 105.3 mph at Montlhéry in 1929.
SPECIFICATIONS
Engine: 996cc (80x99mm) air-cooled V-twin four-stroke; coil dual ignition
Power Rating: 80 hp @ 5800 rpm
Valves: overhead
Fuel System: two carburetors back-to-back in center of V
Transmission: Sturmey-Archer 3-speed, chain final drive
Suspension: girder forks (front); rigid (rear)
Brakes: drum (rear)
Wheels: special Dunlop 28x2.75 inch tires (front & rear)
Weight: 359 lb
Maximum Speed: 120 mph
This Grindlay Peerless record-breaker, powered by a classic 996cc JAP V-twin, was the work of Bill Lacey. The box under the frame holds the battery for the dual ignition.