Bill Connor is widely recognized as one of the world’s leading builders of model I/C engines, specializing in racing motorcycle engines. He has built a number of half-size engines, working replicas of his full-size engines. All measurements of every component are taken from the actual engine making all his models as close to scale as practical. The operative word here is ‘practical’ as all the engines run perfectly. Even though these are large models, no castings are used. Everything is machined from solid.

This model, pictured at the 2012 London Model Engineering Exhibition is of a Velocette motorcycle engine. The original is a 1938/39 works racing engine. Only a few were made and were only given to factory riders of the family owned firm in the Midlands. This design was later developed into the famous post-war KTT engine which was also made available to private riders in 1946.

It is the most significant ‘K’ (for camshaft!) engine. The ‘TT’ showed that it was a production racing replica. It was the first positive stop gear change on a motorcycle, which of course is now standard on all motorcycles.

It is a development of  racer dating back to the mid 1920s and gave the factory its first Isle of Man TT race victory in 1926. Continued development led to several TT and Grand Prix victories. A KTT set the 350cc record at Brooklands of just over 100mph, among successes in the 1930s. The post-war model was the Velocette KTT Mk VIII.

See and hear a KTT at: