yes, you would need quite a powerful fan. these motors are 4 cubic inches, which at 8500 RPM would be sucking in about 10 CFM (quick calculation, there are many more variables such as use of reeds, ease of flow, port sizes, expansion chamber, etc.) . Now there are 12v computer fans that easily blow more than that (around 90-110CFM for a good one) but you also want a fan with high static pressure (something not alot of fans list). I have no idea how static pressures work, IIRC its a complex formula based on air pressure, blade and funnel design, motor power, etc. but in a nutshell I think it means the ability of the fan to keep ramming air into an enclosed area until pressure backflow overcomes the abilities of the fan.
Sounds to me like a reed valve + fan may be your best bet as it will give the fan the longest amount of time to ram air in before the piston descends on the transfer phase (not to mention a reed valve + boost port + fan means that at BDC the fan would just keep ramming air into the engine, this could cause ridiculous amounts of blow-through and kill your milage... pretty easily.
A real turbo will do the same, has incredible static pressure due to its compressor design, will produce an immense amount of blow-through but because of the resistance it introduces into the exhaust, also acts as a power-valve variable exhaust, not only preventing blow-through but giving you ridiculous amounts of power throughout your whole RPM range, not just the top end (though the top will obviously be more noticeable). 2 Strokes have commonly seen 2-4x extra power from the use of a turbo because of this phenomenon. Could you imagine a 30hp HT?
