I have recently acquired a honda cbr 600 f3 which had been running quiet fine the last couple of weeks. About two days ago I noticed that when I reach 5000 rpm in any gear, the bike got a sputter. At stand still when I rev the bike it still sputters at 5000 rpm. Any help would be much appreciated as this is very frustrated. I have read a thread whereby it was mentioned that when the air solenoid valve is bye passed, it solves the problem. I removed the tank only to find that there is no air solenoid valve which I suppose was removed by the previous owner.

 

Welcome to the forum. What do you know about the history on the bike? How many miles/kilometers on it? Any work (besides the air solenoid) done to it that is obvious? Does the sputter go away after getting past 5000 RPM? Sounds like it could be fuel related. Dirty carburetors or fuel pump not performing well.

 

I believe it was used as a track bike, miles on the clock 17 000 and the sputter is still there after 5000

 

Given it's history there is a good chance that modifications have been made to the carburetors. Taking them off and rebuilding them is the only way you're going to know for sure what's inside them and what condition they're in. Since the issue is on the high side, making sure the Vacuum slides are working properly and ensuring the gasket is properly seated is easy to do without taking off the bike. After the airbox is out of the way, 3 screws hold the tops on. Items 20 and 22 on this page. Keep an eye out for the spring, #13, it's trying to push the top off.
https://www.partzilla.com/catalog/ho...tor-components

 

Thanks will start working on it immediately and see what gives afterwards.