Here's an interesting application of the Coanda Effect... I wonder if a smaller version of it could be used to fill the wake of the bike using the engine exhaust:
The Dyson hidden fan in their bladeless fan draws in 42.2 CFM.
For my engine:
For a 174.5 cc engine running at 6500 RPM at half throttle, we'd get 567,125 cc / minute. 567 liters / minute.
The equivalent mass of air will be the same as 283,562.5 cc at one atmosphere of pressure (due to half-throttle).
The volume increase due to temperature increase, assuming 70 degree F intake air and 1200 degree F exhaust gives 1659.67 / 529.67 = 3.133 so we'd then get 1776 liters / minute, which is 62.72 CFM.
A reasonable chemical approximation for gasoline is octane, which has a chemical of C8H18. The molecular weight is (12*8+18*1)= 114.
The combustion formula is C8H18 + 12.5 O2 ==> 8 CO2 + 9 H20. For each 114 grams of C8H18, there will be 12.5 moles of oxygen consumed, producing 8 moles of CO2 and 9 moles of H2O. For gas volume purposes, since equal moles of gas produce equal volume, the volume of exhaust gas replacing oxygen will be equal to 17/12.5 = 1.36.
The volume percentage of oxygen in air is about 21%. This volume will be removed, and replaced by exhaust gas with a "volume" of (21*1.36) = 28.56%. The resulting post combustion volume is (79% + 28.56% = 107.56%) of the pre-combustion volume -- assuming no temperature increase.
So 62.72 CFM * 1.0756 = 67.46 CFM, making lots of assumptions based upon experience with this engine.
So a fully-metal version (to handle exhaust heat) of that Dyson Coanda Effect blower could be used to not only help "pump" the air through the engine compartment, but to mix the exhaust with more air to heat it evenly, then smoothly inject it into the wake to reduce drag.