Datsun Roadster Forum-311s.org

I have a general question. How often does one have to tune/balance the SU's?

should not be too often provided you have a good set, altho different altitude/ambient temps will mess things up a bit. If you are looking for the best "set and forget" I think Weber/Solex is better.

Once set, with the tuning tool of your choice, they should retain their tune until unless disturbed by a failure or accident.
Wear in the butterfly shaft bush will introduce an uncontrolled air leak which you cannot compensate for.
The only way to fix that is new bushes and maybe shafts.

Also depends on how worn the screws and theads are. Before i installed the ztherapy carbs, i was adjusting mine every drive. Fresh plating tightens things up a bit. Once your sure that they are synchronized and set, a dab of blue locktight or cyanoacrylate should keep screws in place.