It is essentially taking the carb off the bike and taking the float bowl off and then setting the height from there. If you're asking how to set the float height, I would strongly recommend you take it to a mechanic to do.

If you're mechanically inclined though, search through the tuning section here and have a look at how to do it for the 250. Once you understand the concept, then look at how to do it for your bike.

One easy check you can do is to make sure you don't have any kinks or weird bends in your fuel hoses, as that may be a contributor.