Really random . . . I have a 93 CBR600f2 my RPM needle floats up and down and I have very little low end. On the top its great but midway through, the bike wont get over 10K. It just started doing this. Any ideas . . .

 

From the year of your bike I guess it has carburettors which would rule out any problems with fuel injection systems. Do the actual revs rise as well as the rev counter reading? It could be an air leak at the inlet manifold where the carbs bolt onto. Other than that then there may be a problem with the electronic system. Sorry I can't be of much help and I hope others will respond soon that may have more knowledge than I do! Hope you sort it.

 

You are right it is carbed and I will check the boots from the carbs to the valves. I wonder if the peg is out of the fitting for the RPM meter. I can't tell if the reeves match the RPM as it floats way too much.

 

might be worth while to check the plugs too