Ignition Advancer

I have been having difficulty with my KZ750H2 LTD idling. I have posted some questions related to this in the Carb forum this week.
This morning, I pulled the ignition advancer and inspected the movement. Everything appears to be fine except on the arms that swing out to advance the timing, there are "inserts" on the arms that contact the cylinder when the bike timing is not advanced. One of these was missing from one of the arms. What do these do? How would it effect the bike running?
Fortunately, I have a parts bike with a complete advancer that is currently visiting some WD-40. I am curious if the new advancer will help the idle.

If those little rubber pads are gone then the timing will be jittery (jump around a little) at idle. It will affect the timing a little, but not enough to notice unless you put a timing light on it.

That was my eperience on a 750 twin anyway.

they are bushings if im thinking of the right part;)

On the 440/650/750/750 twins, there are real small rubber pads on the weights that rest on the cam of the timing advancer at full retard position. It seems like they are getting old and have a tendency to fall off now.