1981 GPz550 ... Which lins are fuel and etc?

Can anyone tell me which of these lines/inlets are fuel and which are vac or drains?

Carbs been off for a while.

Also, what is the port with my red arrow do?

Thanks

Chop

Those carbs have varnish and grunge all over them. You should take them apart to clean, and during that process you can easily figure out what each port is for.

That said, pretty sure the center hose is the fuel inlet, and the two upper hoses are your vents. The small nipple is for vacuum. Honestly though, I'm just guessing.

That's correct. Route the vent tubing so that they don't flop around or let in rainwater. The vents on my 81 650 are routed over the airbox shoulders and fitted snugly between the airbox & side covers. the left vent tube has a frame clamp. The small vac port on #4 is for a vac petcock. If you have a manual fuel valve, you should cap that port. use a good automotive rubber vac cap.

loudhvx has a motorcycle stuff page with a lot of 550 info, especially for the TK22 carburetors. see links in his signature in any of his replies.

As Ed and Martin said:

In the second photo, the hose with clamp, that you see in the middle of the picture is the bowl vent for 3 and 4.
It, along with the similar one for 1 and 2, just route upward toward the place where the tank and seat meet above the airbox. They just sit there, open. The 81 gpz550 has a plastic piece that is mounted under the tank to help hold the airfilter lid closed, and that has two little cutouts for the those vent hoses. The vent hoses are just light vac hoses. There is no pressure on it so it definitely does not need a hose clamp. Yours shows grime there which is not normal. It should never have fuel up that high above the bowl.

The fuel hose is visible to the left side of the second photo, and is in the middle of the rack in the first photo.

The open pipe in the second photo is the vacuum source for the petcock.

The drains are on the bottom of the bowls.

If you follow my links in my signature, you can download several different manuals. I would recommend that. They explain the various hose functions on the bike.