My 289's leaked, and my bike was a very reluctant starter. Much later I remembered Sid Biberman telling me how easy it was to get the float height wrong. If the float height is too high, the carbs leak all the time, and starting is poor. If it is low, things are slightly better, but still not good. My float heights turned out to be 5/8" (about 15 mm) different. You could find out exactly what I did, and how, in MPH, but you aren't a member. This makes your life needlessly difficult: join NOW! You will never regret it.
Here, however, is a shortened version: turn the fuel on. Slacken the clips that secure the carbs to the inlet subs. Rotate each carb on its stub (i.e. clockwise) until fuel begins to runs out of the hole in the carb body, the one partly concealed by the base nut on the body. Now rotate it anti-clock until it stops running. Tighten the clips. (I found this quite difficult to do, so used a different method. However, the desired fuel level is just below the centre of the pilot jet screw and this procedure achieves this. When correct, the fuel level is about 1/32" below the top of the base nut.) If you can figure out a better way to do this, good. Note that a ONE DEGREE "error" in setting the angle of the carb is a 1/16" variation in float height.
My carbs are the ones fitted at the factory, but bored and sleeved by Kevin Traill at Alverstoke Restorations, in England. It wasn't expensive (maybe £70?) and the carbs behave like new.