parts for a streetfighter!

i assume its some kind of breather but i really don't know..any TLS riders, i'd love some help!

when i've finished my studies at the end of the year and subsequently passed, i'm taking 2 weeks off to go for a tiki tour around the island..there are a few places i've never been and some places i've only seen when i was a wee tacker. pretty much i will be heading north from new plymouth, going through to hamilton, then auckland, then up to cape reinga, back down again following the coast around past omokoroa, down through napier and hastings, across to pahiatua and through the ranges just north ...