I'm having the same exact problem with my 2000 600 f4. I just got done taking a ride, it ran great while it was cold, and after it gets to full operating temp it consistently does what you described after I come to a stop, then clears up right about 3k rpm. So, when I got home, I noticed that the fuel filter was only 1/3 of the way full with fuel. Then it got me thinking maybe something is up with the pump or fuel system.

Does anyone know what triggers the fuel pump to come on and when?
Should the fuel filter be completely full of fuel?

I have a small line that comes off the fuel pump that is about a foot long and it doesn't hook to anything. Where does it go or is it some kind of vent?

 

Its weird how so many F4's have the same problem, but nobody has an answer lol. Haven't had time to do the coolant flush nor the coolant hose thing I mentioned earlier. Not sure on your first questions, but the hose thats not connected to anything, I have it too. I'm pretty sure its in case of over fill?

 

when i first got my bike it did the same thing as well i took the carbs out and dismantled them removed all the jets and blew them out, cleaned the float bowls and reinstalled them and its been fine ever since. i also changed the fuel filter with the cleaning.

 

When you clean the carbs and take them apart, do you have to set them up again (besides a synch that is) in terms of pilot screws etc? I wouldn't mind giving mine a good clean (although I'm not sure it needs it) but don't have the experience to properly set up the carbs other than doing a synch with the right tools.

 

+1

I noticed that all my sputter problems begin as soon as the electric fan comes on. My bike runs great while warming up to the point that the fan cycles on for the first time. Once it comes on it consistently runs bad while idling due to the voltage drop. I ordered a new heavy duty rr and I should have it installed by the end of the week. I'll let you know if that fixes my problems.

 

As far as I can tell my F4 has the 'updated' RR (with fins) but I still get it. I'm also pretty sure it's due to a voltage drop which is still odd. I have a 6k Bi-Xenon (although the bulb just crapped on me), heated grips, a heated vest connection and an iPhone charger all hooked up and it runs fine (had it all running during winter) but as soon as the little fan turns on the voltage drops enough to get a stutter.

Is it just me or is that retarded? I can't imagine that little fan using that much power to cause the stutter but it only happens when it comes on and goes away when turns off.

Although the stutter doesn't bother me anymore, I still find it weird.

 

That's a bummer. If I still have this problem I think I may wire in a capacitor like you would use on a car stereo system to stabilize the voltage spike.

Has wonder if anyone has ever tried putting one on a bike? If so, please share.

 

i did a pretty complete dismantle with the exception of the choke
basically removed the vac chamber cap ,spring and diaphram
removed float cap, main pilot jet , floats, and low speed jet
removed pilot screw and cleaned everything making sure there were no worn parts, ripped diaphrams etc. and reassembled i found clogged low speed jets as well as lots of dirt in the bowls.

i did not sync the carbs after but i did put the pilot screw back to factory spec. hope this helps.

 

Thanks, I would only remove the stuff to clean the jets (and not touch the diaphragms etc.). Thanks.

 

If you end up doing that, please post your results here. I wonder if that could solve the problem.