I recently put two new tires on the front of my 1997 Honda c/r v awd they are smaller tires then on back. Now there is a loud grinding noise. Could the different tire size cause this
YES SI WIE YEAH. OU OU. That's the answer in 5 languages.
What you have done is like squeezing your size 12 feet into size 9 sneakers. OUCH!
Use the correct tire size as recommended by Honda by checking the owners manual or the sticker on the door sill and match all 4 tire/wheels sizes as your vehicle is an AWD and they all must match or issues as your experiencing will happen. Any good tire shop will assist you in getting the correct sizes. You will slowly damage the components of the AWD system if you continue to drive it.
You may have already damaged the load differential unit, that is the grinding, I would not drive it anymore until the correct tire size is put back on the vehicle. Like everyone above stated, it is a MUST that all the tires and wheels are the same size on an AWD vehicle.