What ever happened to this

[ClassicBiker]

Any idea what the boxy aluminum horn like structure is that is visible in both photos? Is it to direct cooling air to the top of the cylinder?
Steven

 

[Nulli Secundus]

That would be my assumption Steven. Another feature is the external oil pump on the timing cover. This either says a lot about the inadequacies of the standard Rudge oil pump or the need for this engine to have a good supply of oil to the rotary valve.

 

[clevtrev]

A few explanations here.
http://www.crossmanufacturing.com/history_of_cross.html