marky, My 05, 250 rev 3, does exactly the same, fuel almost constantly dribbling out of overflow spigot below float bowl , I couldnt make sense of the pics either thats just limiting travel of tangs, what i tried was i bent the other little brass tab which actually pushes the pointy plunger (fuel valve) up and off ,up a bit towards plunger to shut fuel of sooner ie lowering the level of fuel in bowl, it still dribbled but not so bad , but engine was pinking and knocking when throttle was rolled off, quite bad, and i did not bend tab a lot , so i gave up and bent tab back to original position . Have read all post on this topic and no one seems to have the answer . does my head in having a new bike and having to watch the fuel constantly dribbling out . dont know if this post helps you but couldnt pass up a chance of a good moan.