Wilsons Sandbox

Hey guys, After troubleshooting my klr for the past week and a half I almost have her running back to normal. However, it has rasied a new problem. The situation: when driving I try to accelerate fast and it doesn't go any faster. My clutch plates are fine and the clutch cable is adjusted properly. I'm thinking that it either has to be the fuel diaphram or the intake duct between the engine and the carb. There is no noise present when I get on it and it runs fine at a stop or slow acceleration its just when I wind her out does this situation happen. I changed the diaphram about 10,000 miles ago. Can it really be ruined already? Any input would be greatly appreciated. And when everything is running ok I'll have to post the whole situation to help others that have put 36,000 miles on their KLR Thanks