My 93 CBR 900RR run decent at idle when you ride it and half throttle its good... but not as fast as when i first got it. It does not feel like it wants to lift up the front tire EVEN IN 1ST. When it gets up to about 7 or 8 grand it just stops accelerating. I have replaced the spark plugs, fuel pump, and cleaned the carbs. The next 2 things im going to do is replace the plug wires and the air filter. Does anyone have any other suggestions? Or does anyone know what the problem might be??

 

do a compression test on it you my be losing compression

 

which could be caused by valve tolerances being to tight

 

I have heard that when the valves are messed up there is a knocking sound ... but im new to working on motorcycles... if the valves were too tight would there still be a knocking sound?

 

no if they are too tight in tolerance it means they would not close all the way thus they wouls lose compression, they dont knock they just wont closeand this is like miniscule ammountsten thousanths of an inch will throw them out