I am attempting the white spacer mod and came across the below suggestion by Lancer. So many have had problems with these screws that I decided to be proactive and have the right tool ready. My question is can I still use this tool if the carb is on the bike or do I need to remove the carb? I have not ordered it yet.  thanks in advance.

you need this small impact driver (HARBOR FREIGHT TOOLS)

for those tiny screws

see the long slim phillips head bit on the right ? that's the one to use
I set the slide on the top of a vise with the needle sticking down through a slight space between the vise jaws
then you can tap gently but firmly and OUT THEY COME !

7 Piece Reversible Impact Driver Set
Item #93481

Only:$5.99

Thanks arteacher but I think I was not specific enough in my question. I have had the tank off before when I checked my valves and plug. I have reviewed the tech section on doing the white spacer mod and that is where I came across the stripped screws problem.  I know you can do the mod with the carb on provided you can get the 4 screws holding the diaphram on and the 2 inside to get to the spacer. What I really want to know is can the impact wrench described by Lancer be used with the carb still on? He mentions using a vise to hold the slider, cant do that with the carb on the bike.  

After you take the top off the slider needs to be removed anyway. I did not need to use an impact driver. I ground a little off the tip of the standard Philips screwdriver to make it more like a JIS screwdriver, held the slider in my hand and using a moderate amount of pressure so the tip wouldn't slip, undid the screws. Be sure the tip of the screwdriver  fits tight into the screw. Any wiggle and you will strip it for sure. Be very careful not to damage the diaphragm. If you do have to use an impact driver you will need a longer bit for it, again with the tip ground off a teeny bit. Then put the slide in the vice so that the needle hangs down between the jaws and the bottom of the slide where the screws are is supported by the jaws. Don't tighten the vice on the needle, just use the vice as support, and tap the impact driver. A third hand to hold the slide would be helpful. The screws should loosen. Another trick to try is to tighten the screw a teeny bit to break the adhesion of the lock tight they use during assembly.
Good luck.

Now I understand what Lancer meant by using the vise. Thanks for all your replies vers, art and gyro. I think I will order the impact driver just in case your other suggestions dont work. Hate to be down while waiting for a shipment. Will post back on my luck or lack thereof with the screws.

How do you get a dremel in there and what tip do you use?

I was unable to remove the screws to access the spacer so I am removing the carb. According to the manual you remove the clip securing the throttle cable and disconnect. I removed the clip and assume you lift up on the cable to release. The problem is there is not enough clearance , it hits the frame before it clears. Am I missing something?  Its an 07.

BTW that clip can fly a long way if it slips off your pliers.  

Best thing to do after getting it  a part is get allem bolts to take the place of the screws