I've got a long Phillips but I can't see the actual screw head for the top right boot/insulator, seems everything is in the way. I just ordered the JIS T-handle screwdriver from Amazon. I went to the link for ST-Riders and that looked promising.
I would think you could to the point of seeing where the clamp is on the number 1 and be able to loosen it. Get a hair dryer in there first get those boots nice and warm.I'm still asking can I pry the damn carbs off.
The top clamp tightens the boot to the carb body, the lower clamp tightens the boot to the cylinder head intake port.The YouTube video is of a 1998 ST1100, and mine is a 2002. I see 2 clamps on each intake. Nothing on the video mentions 2 clamps. I loosened the top one. There was so much dirt and grime that it was impossible to see where the screw was. Have hoses connected to the carbs so removed the bottom one and left others attached and just hanging the carbs. Now to see if I can locate the leak, as there isn't any fluid as I removed everything, will be harder to find the leak.