It all comes down to weight and experience. If your pillion weighs too much plus your own weight it will bog down that 400 motor. And if they are not experienced in ridin on the back. They will fight the flow on entry, during, and exit of a turn, and disrupt the ride. That is were your experience comes in. I always ask if they are familiar with the way a bike handles and will explain to them what to expect during the ride. That way there are no surprises. When you have a person who is comfortable with riding pillion it can be very smooth. Practice, Practice, Practice, as with everything else on the bike. Good luck.