One of the main disadvantages of bound copies of "The Motor Cycle" that are in the Brooklands Museum library is that the advertisements have been removed. A small number of complete copies of the magazine have recently been added to the collection and some of the "small ads" have revealed some interesting machines. The one below from Kings offers a Norton International to racing specification with totally enclosed rockers and valve springs (!) and this made me have another look at an earlier blog.
The "mystery" of the single versus double overhead valve Nortons in the 1937 TT has already been resolved by Mick Woollett but this is an opportunity to add some more to the background. The Norton and Velocette directors were on very good terms and often lunched together. In 1935 the introduction by Velocette of enclosed rockers using the "dog kennel" cambox was so well publicised that when Norton used its enclosed box for the TT there were rumours that it had been made by Velocette. The rumour gained enough credibility that Norton were forced to advertise the fact that it was their own design and manufacture.