I am new to these bikes and am having a problem syncing the 627B carbs on my '73 cb500. The throttle linkage bar (shown in the green box on the attached) moves to the left and right when I try to loosen the adjustment screws. It also changes the idle when the bar slides back and forth. Is it supposed to move or is mine just loosened up over time and neglect? In the picture I've attached is that a pin in the red circle? I've noticed in the newer carbs on the 550s that there is a lock screw in this area to stop this from happening. Perhaps I need to add a lock screw?
Thanks for any help.
Yes there should be a locking pin where you have circled in red. The cover has been peened.
There should be minimal sideways movement of the linkage bar as the locking pin should register into a groove machined into the linkage bar.
If you are able to remove the linkage bar then the locking pin has at some stage been broken. If that is the case then you would need to manufacture another means of locking the linkage bar as getting the old pin out can be a bit of a bugger.
If you can't remove the linkage bar then the indications are that the locking pin is still place but has worn.
