I’m restoring CKW284, the 1938 Manx Grand Prix Scott that was entered by Harrison Town, and ridden by young Harry Smith. He finished in 12th place and his 3rd lap was the fastest ever achieved by a Scott on the Isle-of-Man at 70.03 mph. Although registered as a new machine, the engine was from 1929. To achieve that speed he must have gone well over 100 mph when on fast downhill stretches, with the engine revving at well over 5000 rpm for those downhill bits. It has two Pilgrim pumps, one in the usual R/H door position, feeding the glands and main bearings, etc., and one on the L/H door feeding the cylinder wall oiling. This was copied by the factory later in 1938 for the 1939 Clubman Special Model, which also copied the 21″ front wheel.
The 1926 TT Scotts were of course a couple of years before the introduction of the long-stroke engine for the 1928 TT. Quite what speed they would achieve flat out downhill is debatable, as we don’t really know what their overall gearing was.
My 1938 MGP bike was also the last Scott to finish a TT or MGP on the I-o-M, all subsequent entries failing to finish