Dave

Ok, it's been a while since I had my XT so this is from memory. There are at least 4 cross-head screws holding on the float bowl. They are tight and made of cheese. The inner screws are probably hidden by the secondary carb body. If you have a good cross-head screwdriver of exactly the right length you may be lucky enough to get them out but it's vital that you don't mess up the heads else it'll subsequently be very difficult to get them out, even with the carb' off the bike. You would probably be better off resigning yourself to taking the carb' off the bike and taking the opportunity to look over the carb' thoroughly, there's not much you can do or see with just the bowl off, though you may be able to remove the floats and then look at the float needle which shouldn't have signs of a groove around it - wear could alter the fuel level in the carb' or allow fuel to leak in and make the bike run rich

there ought to be drain screw facing outward on the base of the float bowl. It may be worth draining the bowl into a clean container and looking to see if any muck gets flushed out. If it does (and I assume you too have poor tickover?) the next thing is to check for any dirt in the pilot jet. The hole in this is tiny, so it doesn't take much to block it.

As long as the choke returns to the fully-in position it should be ok but there is I think a seat on the end which bungs-up the choke-circuit to cut off the fuel when running normally. Clearly this seal needs to work or it'll run rich at tick-over when hot.

The carb' is a complicated jobbie, it'd really be worth your while tracking down a manual from the 'net. I think there have beens some posts on this site in the past with places you can download.

cheers

rick