Think about how you'd tell another person two values.
I'd say, "The first value is 38 and the second value is 97." So, why don't you have your arduino do it, but with more concise phrases than "the first value is" (maybe "1" or "a")
It's also usuallly a good idea to send a signal at the start and end of each message - so your message may look like "b1[motor1value]2[motor2value]e"
Then you'd send it with Serial.write(), and read it, one letter at a time, with Serial.read().