Welcome, and I love the color scheme of your Ninjette.
Hard to tell from the picture, but it looks aftermarket, maybe a muzzy?
If your looking for a great WIKI on the Ninjette look over at our brothers and sisters website NINJA 250 RIDERS CLUB, it's one of the best for information on the Ninjette, but some of it is dated, but all is great reading.
http://faq.ninja250.org/wiki/Ninja250_Howto