Hey Guys. i just purchased a 2002 cbr 600 f4i and i am having A LOT of hesitation when i increase speed over 6 grand. some times it runs fine then other times i have a like a huge hesitation problem. its not a problem of not having gas it been a couple tanks now and still problem. i purchased this bike from a guy and it sat in his garage for a year with no one riding it. I think its pluged with rust or what not. is there anything i can clean that out with. Thank you for your help.

-Korey



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does it rev cleanly (without hesitation) in neutral, does the bike have an aftermarket exhaust? I am not a mechanic but it sounds like carburator issues to me. and your bike is fuel injected right? im not sure what the general consensus is on fuel aditives but at a NAPA store you could buy a can of "Sea Foam" which when added to your gas tank in the correct ratio will burn differently then just gas and clean out your fuel system and combustion cambers. but i have heard that when additives arenot mixed properly they can breakdown gaskets and seals so maybe do some homework on that one if you want.
but overal how about a carb cleaning and sychronize? i bet that would help alot. if the bike has an aftermarket exhaust then you could have an exhaust back-pressure issue. aftermarket exhaust cans flow more air than the stock can, because of this the gasses escape the motor/exhaust system quicker than they can enter the system. this creates a "hole"in your power band. if the hesitation is always at 6,000 then back pressure could be the case.
again im not a mechanic but i have had similar issues with both dirty carbs and low back pressure

 

might be the fuel filter or if you have aftermarket exhaust your bike might run too rich or lean which means you need a power commander

 

i think from his avatar, it's stock can.
you probably have rust and stuff sitting at the bottom of the tank. i'd remove the tank, get out all the gas, clean it, dry it, and change the fuel filter.

total pita changing that filter mang!
T

 

I have this same issue but @ 9k rpms on my 600RR totally stock did u ever find out what it was?

 

i had same problem (6k and it would miss and hesitate) It would also backfire and spit flames... ANYWAYS

CHECK your spark plugs that fixed my problem, also check your airfilter.

 

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