Float level spec is 16mm, with the carb at an angle so the spring in the needle is not compressed. This works out to be where the seam in the float is parallel to the bottom of the carb body. If you have issues with overflow you can go a mm or so lower (17-18mm). Check that the floats are straight and not twisted.
thanks & yes i do have overflow problem, also its hard to start from cold, once its been started its fine been told to check the bowl hight before i do anything else so i'll check that after