What gauges? I have this water temp gauge:
http://www.ebay.com/itm/like/380774278868?lpid=82
The sensor that comes with, IIRC, directly fit into the stock port of the Ninja's Stock temp sensor.
BTW, I am doing a custom gauge set up. NevadaWolf, are you saying that is the thread size for where the stock oil pressure sensor goes? I am unsure of that size thread.