Graves Motorsports Yamaha R1 Top Velocity Stacks for the 2009 - 2014 models. This "Upper" or "Top" velocity stack is sold separately from the lower billet machined piece shown in picture. The upper stacks must be used with a YEC ECU or Flash Tune and correct setting will be supplied to customer upon purchase.
- Developed by Graves for your Cross Plane Crank Yamaha R1.
- This stack kit improves power throughout the entire RPM range.
- The staggered tops allow the cylinders to share the available volume of air in the R1's air-box evenly at low and mid range RPMs.
- The shorter-than-stock lower stacks (sold separately) feed the R1's appetite for big air when the upper stacks raise improving top end power.
- These stacks were specifically developed on the Graves Yamaha Superbike give their riders the drivability needed to win races.
- Notes: Both "Upper" and "Lower" R1 Velocity Stacks are designed to work together. The items are sold separately as you can use the performance-designed lowers with the stock uppers (uppers cannot be used with the stock lower stacks).
