A thread on these here I’m sure just not finding at this time.I ordered some McCasster Carr plugs to try in the plugless side covers in my collection.They’ll work fine as is for these.However,if your mounting the side cover using these,I’ve found carefully shaving 3/32 off the back is necessary.They are to tight against carb and push the dome out to far for correct appearance. I personally don’t remove original blued plugs. I like them that way.Should you need only a couple few for your project I have some extras and would gladly send you a few to try but you have to do the cut.Pm me,I’ll donate the stamp.Obviously your call if you like or not.Ride safe!