I can read registers but not be able to write. How it is pos

Ok I know the mpu6050 enter in sleep mode when power up, I try to connect with a pic microcontroller and can read registers that are not zero when power up, I read register 117 that contains the slave address, read the 107 decimal register too that contains power management1 register, my value is 64 in decimal that means that the mpu is in sleep mode. I even can read registers from zero to thirteen that doesn´t appear in the datasheet but when I try to write register 107 to disable sleep mode I can´t write and this is very strange because for readings I need to use commands to write with the only exception of the byte value to write.
My question is, is there any other register to modify for be able to read the accel and gyro measurements?
If anyone had the same problem I would be very gratefull of his/her help.
Thanks, I`m Fran