Hi, I have a 96 CBR600F3, purchased the bike in 2000, and never had any issues with the bike till now.
Last fall I forgot to winterize the fuel (I know bad move on my part), so this spring when I started the bike up, it ran like crap, and backfired like hell. I changed the fuel, it still ran really bad till it burned off the old gas still in the lines and carbs but then ran so so but better.

Last Weekend I changed the fuel filter, sprayed a whole can of carb cleaner thru the carbs while the bike was running,
and changed the plugs. The bike ran perfect for about 20 miles, but now I noticed its not running smooth again.
I think its fouling plugs. Running at cruising speeds its fine (50 MPH) but riding at extended slower speeds, and stopping at lights,
the bike runs bad and a few times seemed like it wanted to stall.

Does this sound like I may need to have the carbs taken apart, soaked, and rebuilt as there may be a varnish buildup?

Thanks in Advance...

 

How do the plugs look? you migh have fouled them with the carb cleaner/bad gas combo.

 

I didnt get a chance to check the plugs tonight, but I purposely changed the plugs last as to not foul them with the cleaner.

 

I know that many people clean the carbs with the carb cleaner without having to take them apart but in my own expirience its not such a good idea nor metod. If you are doing something you might as well do it ones but properly... The problem with the carb cleane is that it kills the ruber O-Rings inside the carbs especialy if you use too much of it. So in your situation most likely you are running too rich now and thats why the bike behaves the way you describe. Or may be the rubers needed to be changed at that stage anyway. So, your best bt is to take the carbs apart wich will give you a chance to make sure they are clean and nothing is blocked and make sure that all the o-rings are nice and tight fit in the carbs. If they became plastiky they wont be doing the job they should be doing any more and most likely the bike will be running crap(especialy on low RPM's).
Now, take that sucker apart and show it who the man realy is...
Good luck.