whats this pipe and rattle noise?

[400zxrste]

hi guys, new to the zxr scene.
i have recently bought a 1999 t reg zxr 400 as my first bike. it has a rattle on the engine on the right hand side, so i thought cam chain tensioner but on inspection saw that it was nowehere near touching the caseing so assume its ok. any ideas as to possible noise? but have also found this pipe, completely disconected and cable tied to the engine. any ideas as to what and where it should go please?
any help would be gratefully recieved

[banner001]

i know this has been asked before so ill be brief, that pipe goes from the carbs to your water pump, the black thing with the gold band at the bottom is the one-way-valve...the gold bit wants to be connected to the water pump, the free end of the tubing goes to the carbs.

rattling on the right side is probably the clutch plates in the basket - no big deal, they all do that. i assume its more apparent on startup and at idle?