RC - what you say is not really right, the 2C does not crank twice, the shaft would have turned 360 degrees for every power cycle, the 4C engine would turn 720 degrees. The 4C engine has proper combustion cycle in that the fuel so called completely burnt.
Four stroke engine:
Try this -->
http://www.k-wz.de/vmotor/v_omotore.html and this -->
http://www.keveney.com/otto.html
Two stroke engine:
try this -->
http://www.keveney.com/twostroke.html
General difference between 2C and 4C is:
RPM - 4C is usually running at 10,500 RPM max but 2C is generally about 12,000 RPM, some can even touch 22,000 RPM.
Torque - 4C has more torque at a certain RPM than a 2C engine of the same capacity, 4C torque also comes at a lower RPM
Fuel - 4C has a lower fuel consumption
Maintenance - 4C needs more care in operating and maintenance
Tuning - both are the same in terms of ease
They are very different creatures but both have their own purpose.