!981 Carb Line Questions

Hey Guys-

I finally got my carbs clean and ready to reinstall for my first fire up. I was wondering if I could get some help on what all the ports on my carbs do. I know one is the main fuel line hookup. However, who can tell me what there four are? Are they overflows?

Also I'm switching to a gravity petcock instead of a vaccum petcock, which lines on the carbs are vacuum for the petcock?

Thanks
Josh

Sorry to sound critical but those carbs don't look very "clean" to me.

Rebuild tutorial here... zeus.mtsac.edu/~cliff/storage/gs/Mikuni_...Rebuild_Tutorial.pdf

-Did you remove the pilot jets and hold them up to the light to make sure the orifice is open?

-Remove the pilot screws and jets and shoot carb spray up through the orifice and verify the sauce comes out the small holes in the carb throat?

- Verify the choke pick up tube is clean and that the passage is open all the way to the choke plungers?

- Did you replace all the various O-rings?

Sorry if this sounds critical, just trying to help you avoid all too common problem of having to clean the carbs twice (or three times).

Regarding your question: the four brass tubes near the pilot screw are vacuum ports. You need to plug them with caps.

Nessism wrote: Sorry to sound critical but those carbs don't look very "clean" to me.

Rebuild tutorial here... zeus.mtsac.edu/~cliff/storage/gs/Mikuni_...Rebuild_Tutorial.pdf

-Did you remove the pilot jets and hold them up to the light to make sure the orifice is open?

-Remove the pilot screws and jets and shoot carb spray up through the orifice and verify the sauce comes out the small holes in the carb throat?

- Verify the choke pick up tube is clean and that the passage is open all the way to the choke plungers?

- Did you replace all the various O-rings?

Sorry if this sounds critical, just trying to help you avoid all too common problem of having to clean the carbs twice (or three times).

Regarding your question: the four brass tubes near the pilot screw are vacuum ports. You need to plug them with caps.

I should've specified, I snapped that photo directly after pulling the carbs off the bike, they aren't cleaned yet in that photo. So no offense taken, I would certainly not install them back into the bike in that condition.

To answer your concerns, yes, all pilots checked with drills, all passages and other jets confirmed open and clean, All new o-rings and gaskets, bodies brushed, cleaned and new screws installed.

As a side note, here's how gunked they were. They needed a very good cleaning.

Please scroll down in the carb section and find"GPZ550 carb work" ..... in that thread Patton put up a real nice pic where wired george explains the ports on these.

I used this for my 82 Gpz 750