Cut wire #53 on the ECU harnes to disable the 180 kph speed cut. The wire is yellow-green with a silver trace. Insulate the bare ends with tape. Maybe wire in a switch to enable / disable the speed cut.
Note:
This impacts the HICAS diagnostic mode - will not exit the diagnostic when 10kph is exceeded.
This mod is only for legal off street activities - ie drag racing, circuit racing, speed trials (eg the annual Ohakea trial) or if you live in a country where the speed limit is over 180 kph.
It is up to you to ensure your engine does not run lean at high speed - you will loose your engine if it does.
courtesy: http://www.overflow.250x.com/