This was a common problem on ZX chassis Skidoos after they aged. It generally was caused by burnt brake fluid (not changed frequently enough) clogging the return hole. I have no idea, but just wonder if something similar is occurring. On my 06 Attak, I hardly used the brakes due to engine braking. Driving those hard you would just roll out of the throttle to set the ski and start the turn and the roll back on to complete the corner and come out full tilt. Geez, I miss that sled

However I am guessing the Viper and Sidewinder have to use the brakes more like a 2-stroke.