Chainsaw Repair

OK, the relationship between CCR and V_C/V_S is straightforward, but I'm not sure what you are calculating with the rest of it. 

yes, straightforward.  to get the CCR and Vc/Vs, you need just two things.  case bdc volume, and swept volume.  a plot can easily be made for different volumes.  taking it a step further, put rpm in the mix at peak DR.  peak DR, for any motor has to be below peak hp rpm.  there is a slight rise at peak tq.  check the curves in the paper.  blair shows this much clearer.  for a high rpm motor they are pretty flat.  used that single rpm or close to it in my graph.  a user input value.  best guess.  that rpm, is placed between values of rpm, in 500 increments.  after peak torque rpm, the time*areas of the ports are getting too small. so, the time*area is in control.  the rpms are showing what the CCRs an Vc/Vs would be along their curves if there was air enough.  nothing fancy.

it is a close estimate.  until someone figures out the heavy math, best that can be done, as i had mentioned before.  since the Vc/Vs is always going to be a curve, and CCR is always a straight line.  they will never line up with rpm and the case volume, to the right of their point of intersection.  none of this matters at all, unless you really like to make things go, by balancing the case to the porting using rpm.