CSR Chopper:
I also have an '82 CSR, and have considered using a 16" rear rim with the front hub to build a front wheel . Both front and rear hubs have 48 spokes, so that will work. One problem is the spoke length will need to be shorter than the front spokes, and longer than the rear ones so new spokes will need to be ordered. Our present front tire size is 100/90-19, with an overall diameter of 26.1". A 110/90-16 tire is about as large as will fit the front fender. The side clearance will be close, and the spokes will need to be tensioned very precisely to get the wheel perfectly centered. Also the 110/90-16 tire will be only about 23.8" in diameter, so the front of the bike will be lowered by about 1 1/8", and the speedometer will read 6 MPH fast at 60. It can be done, but only by a very qualified technician who takes great interest in getting it right.
Your reasoning might be appearance, but mine has to do with the wheel width and handling performance gained therein. Our present 19" wheel is only 1.85" wide. This allows the front tire to move slightly from side to side. The 16" rear wheel is 3" wide. Most modern sport bikes use a 3.5" wide front wheel with 120 size tires. The 3" wide wheel will support the tire very well and improve handling and steering response. I believe the narrow wheel width is perhaps the one greatest shortcomings in handling between our old KZ bikes and today's modern sport bikes.
Bill Baker
Houston, Texas
1982 KZ650 CSR
2008 Yamaha FZ1
2006 Yamaha FZ1
1977 Honda Supersport 750 four (sold)
1984 Honda Nighthawk 650 (sold)