carb balance screw jiggles loose

[working class choppers]

in the middle of the rack there is a screw which adjusts the throttle position
and keeps the carbs in balance where the pivot on the connecting arm
there is a pin/spring/clip and a bolt on top the adjusts
i have it set, holding a good idle, reving and riding well
after about a mile or so the screw vibes out and i am idling rediculous high
anyone experience this? have a fix?
looking at the fiche
http://www.starmotorcycles.com/partviewer/default.aspx?ls=star#/Yamaha/XS650E_-_1978/CARBURETOR_XS650E/XS650E_(1978_MOTORCYCLE)/CARBURETOR_XS650E_(XS650E_-_1978)

i looks like there may be a spring needed under the adjusting bolt?
#43 and #44 in the middle
this fiche looks a little different than my carb as i have another arm and spring/screw setup
similar to what is on the outside of the left carb
thanks in advance for the help

 

[5twins]

Both the pin and the adjusting screw should have a spring on them .....

They mount in the "C" shaped bracket on the right carb. The left carb just has a tab that fits between them. This pic is of a BS34 but the 38s are the same.

 

[working class choppers]

thanks
will need to get something in there
great pic man

Both the pin and the adjusting screw should have a spring on them .....

They mount in the "C" shaped bracket on the right carb. The left carb just has a tab that fits between them. This pic is of a BS34 but the 38s are the same.

 

[swoop_racer]

in the middle of the rack there is a screw which adjusts the throttle position
and keeps the carbs in balance where the pivot on the connecting arm
there is a pin/spring/clip and a bolt on top the adjusts
i have it set, holding a good idle, reving and riding well
after about a mile or so the screw vibes out and i am idling rediculous high
anyone experience this? have a fix?
looking at the fiche
http://www.starmotorcycles.com/part...MOTORCYCLE)/CARBURETOR_XS650E_(XS650E_-_1978)

i looks like there may be a spring needed under the adjusting bolt?
#43 and #44 in the middle
this fiche looks a little different than my carb as i have another arm and spring/screw setup
similar to what is on the outside of the left carb
thanks in advance for the help

Do you know what size that screw is, I seem to have stripped mine

 

[swoop_racer]

Anyone know the dimensions of this screw or where to find a new one?

 

[fredintoon]

Anyone know the dimensions of this screw or where to find a new one?

Hi swoop,
if the screw's thread is stripped it's more than likely the threaded hole it fits in is stripped too.
I'd tap it out the next size larger and fit a fatter screw to match.