If only that were possible..Hmmm. I assume you are talking about the cadence that YOU as a cyclist are happiest at?
I ask, because if you have a normal yamaha PW motored bike, then once you get up in the 90RPM range, you are getting very little assistance from the motor. Its most powerful at around 75RPM, but virtually useless over 100RPM.
The Bosch (especially CX) will go higher.
Sounds like you need to swap motors around