wont rev past 3000 revs?

wont rev past 3000 revs?

hi guys, recently bought a 92 yamaha super tenere 750.
will fire up and tick over no problem but when i rev it past 3k revs just splutters , the bike has been lying up about a year. drained fuel and put fresh fuel in, changed plugs, tryed cleaning out tank as best i could. getting a good spark from plugs, took out carbs and romoved bowels from end of carbs but looked clean. also took out jets and blow them out. air filters are clean. so any help would be great :thumbsup2:
Source: irish bikers