The adjuster tool works in conjunction with the stock engine control module to reprogram the fuel mapping to tune a Yoshimura exhaust and other modifications. Yoshimura's tool is AMA Supersport legal and does not "trick" the stock ECM to change mapping nor does it have to remain installed on the motorcycle after tuning is complete. Injection sensors will function properly at all elevations and weather conditions. The adjuster tool connects to the stock wire harness to allow changes. Once mapping changes are made, the tool is removed and then can be used on another Suzuki motorcycle - a must have for any performance tuning shop. The tool adjusts the fuel map at four points:

• Slow speed idle/cruise
• Mid RPM acceleration
• Low RPM acceleration
• High RPM acceleration

Download Instructions: R-421 Instruction Manual (PDF)

Model	Year	Description	Part #
GSX-1300R	99-07	EFI Adjuster Box	R-421
GSX-R1000	01-02	EFI Adjuster Box	R-421
GSX-R750	99-03	EFI Adjuster Box	R-421
GSX-R600	01-03	EFI Adjuster Box	R-421
TL1000R/S	97-03	EFI Adjuster Box	R-421