As it happens, the outer circumference of the primary seal cup had prematurely swelled and flattened. The distance between said cup and the pressure port was less than normal, yet Suzuki couldn’t determine if this discovery was a causal factor. Additional testing revealed that the primary seal cup may flatten when the brake lever is fully released. In this scenario, the primary port may become blocked, resulting in more travel.
Suzuki modified the position of the primary port in February 2022 to increase the distance from said port to the primary seal cup with the goal of preventing blockage. The American distributor informed SMC of a field report alleging excessive brake lever travel and spongy brakes in March 2022, with two additional reports issued in April 2022. A plethora more followed suit through December 2022 according to documents filed by Suzuki Motor USA with the federal watchdog.
Better late than never, January 2023 saw the Japanese manufacturer discover the root cause for this condition. Suzuki determined that a compound in the cap diaphragm could migrate into the brake fluid, leading to primary port blockage and increased brake lever travel. Suzuki Motor USA also determined a noncompliance with motor vehicle safety standard 122 for motorcycle braking systems, namely extended braking distances.
Manufactured by Hitachi Astemo, the suspect front master brake cylinder bears part number 59600-10L00 as per the document attached below. It will be replaced with a brand-new one by authorized retailers, a front brake master cylinder with a repositioned primary port. In other words, the Japanese company took just around a year to decide on replacing the bad part with the revised part introduced into Hayabusa production a year (!!!) ago.
Only the 2022 model year Hayabusa is called back, namely 2,552 examples of the GSX1300RRQ/ZM2 produced to U.S. specifications between March 2021 and January 2022. Dealers have been informed of the recall on February 27th, whereas affected owners will receive first-class mail notifications no later than March 1st.
The 2022 model year 'Busa continues to be listed on Suzuki’s American website at $18,599 excluding the $440 destination charge and $150 freight surcharge. The 2023 model is a little bit more expensive at $18,799.