pilot fuel screw, adjustable??

[roost]

Again, working on a 1980 gs 750.

After going through the carbs:
-cleaning
-new o-rings
-bench synch
-pilot air screw', 2.5-3 turns out

In addition to the 'pilot air screw', is the "pilot fuel screw" also adjustable? (1 turn out?)

When I bought the bike this summer, I cleaned the carbs, but don't remember adjusting the fuel screw, so it's probably all the way closed.

Would that explain my bikes poor idle and need to use the choke?

Learning, be patient with me

[Nessism]

If your bike is actually a 1980 it will have BS CV carbs, which don't have fuel screws.

[Steve]

You don't have "pilot air screw" and "pilot fuel screw" on your carbs.

The pilot air JET is in the intake of the carb throat and should be installed snuggly. NO ADJUSTMENT.

The pilot fuel JET is in the float bowl, next to the main jet, and hidden by a rubber plug. It is to be installed snuggly. NO ADJUSTMENT.

The only thing that you CAN adjust is the "idle mixture adjustment screw", which is just above the outlet of the carb. Start with it three full turns out from lightly seated. When the bike is warmed up, slowly turn each MIXTURE screw in, listening for a increase in engine speed. After it speeds up (it may not be much, maybe 50 rpm), listen for a decrease. Stop there, back up about 1/8 turn, go to the next carb.

All the MIXTURE screws might end up about 2 to 2 1/2 turns out, but the bike will start easier and run better while cold if you start at three turns.



.

[terrylee]

I believe being 1980 means it only has a pilot air screw and no fuel screw. At least that is the case with my 850s. Did you say you had synced the carbs? If not that will make a huge difference. terrylee

[Steve]

I believe being 1980 means it only has a pilot air screw and no fuel screw.

No, it does NOT have a "pilot air screw".

It has a fuel JET and an air JET and a MIXTURE SCREW.

.

[roost]

I was reviewing a carb rebuild tutorial, which was a different model, which had an fuel screw, hence my confusion. Easy enough.

[chef1366]

Idle mixture screw.
The air and fuel is premixed using the pilot air jet and the pilot jet.