1. I wanted to know if i can put in a handle bar riser to raise the handle height on a Apache rtr 160.
2. What precautions should i take.
3. Is there any side effects because of this change on the handling.
Yes you can fit a handle bar riser. The difference in handling would depend on how high you decide to go with your setup. Please post some snaps of the riser that you are planning to fit.
