Yamaha YZF-R1 Graves Exhaust, Power Commander V and ECUnleashed | Literbike Mods

Inside the Yamaha R1 ECU are three CPUs (Central Processing Units), each essentially a tiny computer complete with memory. One CPU manages only the YCC-T ride-by-wire throttle, while another looks after everything else: injection, ignition, the YCC-I two-position intake stacks and all other operations. The third CPU oversees the other two, making sure everything works properly and ensuring that the YCC-T doesn’t malfunction. Because Yamaha, along with most other manufacturers, does not disclose the exact internals of the ECU or the CPUs’ programming, the ECU must be hacked in order to find the maps—a lengthy process. First, the ECU is cut open and the circuit board potting—a coating that protects the internals but also covers and hides everything—removed. This reveals the circuitry and components, and from here a way into the CPUs can be found. The R1 ECU, for example, allows access through debugging ports that are wired to its external connectors. Other ECUs, however, may require a different avenue or even additional wires soldered directly onto the board.

Once the CPUs are accessed, the internal memory containing coding and data can be downloaded to a computer and examined. But rather than an obvious program and maps, the output is simply a vast array of numbers that must be deciphered. There is software available that helps with this decoding, but it’s still a lot like looking for particular clumps of hay in a haystack. Even once a map or bit of software is discovered, some detective work is required to find what each does—for example, a piece of coding that points to what looks like a map may also point to a port on the CPU; that port may in turn be connected to a pin on the ECU’s connector that routes to the throttle position sensor, indicating the map relates to the TPS. As you can imagine, the entire process can become very involved and lengthy. Beau Braunberger, who looks after this code work for ECUnleashed, revealed that the R1’s ECU contains 80 maps in the YCC-T CPU and another 230 in the EFI CPU. These maps cover everything from the crucial injection and ignition functions for each cylinder to mundane operations such as the AIS valve. The R1 has every map duplicated; in U.S. bikes these maps are identical, but in Japanese bikes, for example, one complete set of maps is unrestricted while the other is the 100-horsepower restricted version.

With access to all the maps as well as the programming and even whatever unused parameters may be available, some interesting modifications can be considered. ECUnleashed is working on a quickshifter using the stock ECU, while Braunberger’s personal R1 is set up with cruise control, all through the stock ECU. The possibilities for tinkering are almost endless, especially with as powerful an ECU as the Yamaha has. The Yamaha’s ECU is made by Hitachi and the two main CPUs inside are made by Renesas—a company owned by NEC, Hitachi and Mitsubishi. Similar CPUs can be found in various Suzuki and Kawasaki models, meaning most can be dissected and reflashed in a similar manner. Honda ECUs, however, are made by Keihin; Braunberger calls them throwaway ECUs as there is no easy way to access the internals to pull out the coding and maps—that’s not to say it can’t be done at some point, however. Interestingly ECUnleashed closes any access to the ECUs it reflashes, meaning the changes made by the company cannot in turn be extracted.

Sportbikes may be a few years behind the automobile world in this area of performance modifications, but companies like ECUnleashed are rapidly making progress. Expect this to be a more common modification in the years to come—provided the manufacturers continue to allow some form of access and/or innovative programmers continue to work their magic. SR