If straight-line speed is your priority, the RS 660 takes the lead. With 28 HP more than the ZX-4R, it offers a more spirited ride that will be noticeable on highway overtakes or track days. When it comes to agility, the RS 660 has a clear advantage. Weighing in 6kg less than the ZX-4R, it will feel significantly easier to handle in low-speed traffic, parking maneuvers, and twisty corners. Riders with a shorter inseam should lean towards the ZX-4R. Its seat height is 20mm lower than the RS 660, making it much easier to flat-foot at stoplights and increasing confidence during stops. Bottom Line: While both are capable, the rs660 offers a superior power-to-weight ratio, making it the more exciting machine for experienced riders.
| Spec | RS 660 | ZX-4R |
|---|---|---|
| Displacement | 659 | 399 |
| Power | 105 | 77 |
| Cylinders | 2 | 4 |
| Weight | 183 | 189 |
| Seat height | 820 | 800 |
| MSRP (US) | 11749 | 8999 |