I know that the topic of this particular thread shifted a bit, but i want to post this for future reference to show others what has been done:
In early 50's there was a racing car called Tatra 607/2 monopost built to F1 specifications of that time. Its air-cooled V8 engine vas first cooled by two fans, but later they applied ejector technology, what is using stream of exhaust gases to such the air through cooling. That saved approximately 20 hp of this 200 hp engine. You can find reference here:
TATRA 607 F1,Formule 1, construct, okruhy, závody, grand prix | Constructors F1,
https://en.wikipedia.org/wiki/Julius_Mackerle
Pet motoru z ceskoslovenska (czech only, sorry).
Now why I am still sceptical:
- they used exhaust gases to replace cooling fans only. so applying to the part of aistream that already was "draggy", not adding another ducting to move more air to fill the wake (and Ledwinka knew enough about wake, as he worked with Jaray)
- although i don't doubt the exhaust gases were able to transport large volumes of air, I suppose they didn't produce much of "sucking pressure". Air cooled engines have cooling fins much less dense than common water-cooled radiator is. Therefore i worry that it would severely reduce performace in common water-cooled radiator cooling
- the idea you proposed is not new in its essence . It has been done - the T607 is living example - and it is well documented. But it was - despite its remarkable results (T 607 were unbeatable cars of its time) - abandoned. IIRC it was because it works properly only in narrow set of conditions. Have too low rpm and your engine will overheat, have revs too high and you will overcool.
- From the above stated reasons I must conlude, that it is probably idea not worth to pursue - otherwise bike disegners would already applied it.
I dont want to be a spoilfun. You asked us our opinion and each of us tried to
answer as honestly as he could. It is definitely doable, but it is too much effort with too uncertain result. But, feel free to go ahead.
BTW - Anybody knows how to solve Navier-Stokes equations? If they solved it in the fifties...