79 carbs

[tazcu]

i'm putting carbs on my 80 xs1100...carbs from a 79...extra lines and not to sure where they go?...plus do i have to use 79 air box?...is there a diagram on here for it?...pilet jet screws should i turn them out about 1 1/4 turns for starter...ty...Tim

[Ken Talbot]

The extra 'upper' set of lines are atmospheric vents for the float bowls. The bottom lines are still fuel lines. Run the upper lines to the nipples on the forward, upper half of the airbox. You will also have to drill out those nipples so they in fact do vent. When they changes the carbs in '80 to a different bowl venting system, they left the nipples on the airbox but didn't drill them open.

[randy]

Yes, Tim. Lightly seat the pilot screws and then turn the pilots out 1-1/4 turns. That should get you in the ballpark. Some motors like it lean, some like it rich so you may have to fiddle with them for a while.

First, synchronize the carbs.

Lean symptom:

**This assumes you have no exhaust leaks at the head or holes in the pipes**

If the exhaust pops on decelleration, it's running lean, turn the pilots out in increments of 1/4 turn, then ride it. Repeat until the popping goes away.

Rich symptom:

Bike on center stand, not in gear, if when goosing the trottle, the idle hangs high and slowly decreases to normal, it's running rich. Turn the pilots in in increments of 1/4 turn, goose it. Repeat until symptom goes away.

After you're done with all that, synchronize again.

Have fun!

[John]

Another thing to remember, the 80 carbs use main jets sizes that are much smaller than the jets that are in the 79 carbs. That is because of the different midrage circuit in the 80 as compared to the 79. Don't change the main jets. If you do, you will have a very lean condition at most throttle positions. I have done the something to my 80SG. I had installed carbs from a 78E and didn't alter the main jets until I did an 1179cc big bore kit.