R6mad08

Hi Guys, Please say there is some out there that can help me? I purchased a 2000 r6 deltaboxII a week or so ago the guy i bought it off had to put a new set of carbs on as the previous oned had been dyno jeted and the brass bushes had gone so obviously the bike was over fueling! The new carbs are from what i can tell and what has been said by the seller are standard they still hav the yellow paint on the adjusters. Now the bike was runnin fairly ok but not perfectly cut out on me once or twice and had problems re-starting the bike it wasn't idleing neither was it reving! So a mate of mine balanced the carbs for me yesterday revs alot cleaner when in neutral but was miising like crazy in the mid-range when riding, so changed the plugs this morning fit some iridium NGK 10EIX in exchange the current pluggs did need changing totally black at the spark end! I then took it out for a test run straight away to find that it was now even worse missing like a bitch cant take it passed 6000rpm and now its not willing to go anywhere no revs what so ever its overfueling like crazy!? My next attempt is to change the leads as they do admittantly look pretty worse for wear, or am I looking at the wrong place is there a possibility it could be something else causing the problems, really frustrated now as cant use the bike at all!? Please help Cheers Gareth