This tip is to remove the springing in the ends of the throttle arms, the ones with the round alloy arms.

I have no idea why Honda decided to do it this way on the early bikes.  It causes operating problems and difficulty synchronising them.

On my own carbs, I remove the capture bolt from the ends, then take out the spring and the sprung pad.

First cut the spring so that it is just below the end of the spring guide on the pad. You still need the spring on there to make up the diameter.

Now you need some brass or alloy rod. You need the brass pieces to be just long enough to hold the pad against the pin, without exerting pressure on it. If you can find some 5mm diameter, that is perfect. If not you can use 3/16". I guess tubing would be even better as you could eliminate the spring, but I have not tried that.

Offhand I can't remember how long the rod piece was - not very long.

You will only be able to to either fit or remove the arm with the cap loosened, but that small inconvenience is far outweighed by the improvement in the throttle action.

This takes a lot of slop out of the movements and makes throttle control much more positive.