GPZ550 Vacuum switch/valve?

What exactly does this piece do, and is it necessary?

I'm assuming it's for the factory airbox, but I'm unsure since my bike came with pods installed from the previous owner.

The engine is from an 81

pic from google

It looks the same as the vacuum switch on my bike (83 KZ1100). Its for emissions and can be deleted as long as you plug up the openings for the hoses. That's what I've seen on other kz1100's (or KZ1000's) anyway. Without the factory air box it is not connected to anything is it?

kzrider.com/forum/3-carburetor/605822-re...rol-on-kz1000-police

Ah nice, looks like PO already did half of that.

The breather hoses are still connected to it, but there aren't any vacuum hoses going to it so it's not doing anything.

I'll finish that job and remove all that

In case it isn't, make sure the breather on top of the transmission is able to breathe. Sometimes people mistakenly plug that too, but it must be open.

loudhvx wrote: In case it isn't, make sure the breather on top of the transmission is able to breathe. Sometimes people mistakenly plug that too, but it must be open.

Yes, you're right. That one I planned on positioning a hose over the chain