Vacuum Lines

[excess11]

The vacuum advance on my bike rattles back and forth when at idle. Where should the vacuum line from the advance unit be connected. I do not know if it is hooked up to the propper vacuum source. Why does it do this?

[MAXIMAN]

On my XJ1100 it goes from the #2 intake boot vaccum nipple to the vaccuum advance

[randy]

On the XS11, the vacuum advance hose goes on the #2 carb, NOT on the manifold. The nipple on the carb supplies metered vacuum based on throttle settings. The manifold nipple is a direct cylinder connection, used for balancing (synchronizing) the carbs. If you hook up your vacuum advance to the manifold nipple it will make your advance rattle.

Don't know about the Maxim.

[dntemp_ca]

This seems to be a fairly common observation on the XS11. My 78E was doing that, too. Drove me crazy. Still rattles a bit, but only at certain rpms and not severe at all. First thing is to make sure the vac hose is connected to the proper nipple...on #2 Carb. What made mine better was: Cleaned and synced the carbs. Made sure there were no air leaks at the manifold. Replaced the vac hose ... hose had some cracks near the nipple coulda leaked a little. Made sure the nipple hole is clear on #2 carb. The hole at the bottom of this nipple is tiny and is so for a reason...to dampen or smooth out the air pulses. I also took the vac advance off and cleaned up and lubed the mechanical advance mechanism. Was pretty gummy after over 25 years. I don't know which of these actions had the greatest affect cause I did most of it at one time. But the vac advance action is much smoother now.

[Dennyz]

I fixed the rattly advance on my "F" by cleaning and greasing it.