why does my Suzuki GSX-R 600"stumble"in 1st gear?

it's a 98'GSXR SRAD 600 and it only has 7000 miles.it pulls hard and fast the entire tachometer through every gear besides 1st. 1st gear pulls hard up until 8K RPM's, and then the engine sort of stumbles, or acts as if it's being choked to death or something. i usually just shift into 2nd before i even get to that point so i dont have to deal with it.what is the problem and why did it happen?please be as specific as possible, and check my stats, i always select the best answer.i did say it in my posting. all of the other 5 gears pull hard and fast all the way through the tachometer. my bike runs like a DREAM ExCEPT for that spurt at 8K in 1st gear ONLY. had NGK spark plugs put in 4 months ago. just had carbs cleaned. bike is STOCK, there are no goofy wires and filters and boxes and commanders and stuff like that. EVERYTHING is stock, even the exhaust. what could the problem be?

you did not mention whether you noticed this problem at 8K rpm in other gears... if so then I have to ask about engine mods airbox.. intake , exhaust power commander... have the plugs been changed recently?? ant number of electrical gremlins could be at work....send me an emial or IM i may can help...