Hello Everyone,
I was wondering if anyone would he able to help? I have a 2000 Cbr 600 F4 and when the coolant needle gets to around 3/4 of the way to hot and the cooling fan comes on the bikes rpms go up and down, the lights dim and most on the time it dies. The bike will start right up again but as soon as the cooling fan comes on I have the same problem. This problem is only happening when the cooling fan comes on. If the bike is having this problem and I throttle up to 2000 rpm the bike seems fine(lights get brighter rpms steady) but then I throttle down and the same problem happens. The idle on the bike is at 1500 RPM. Thanks for all the help.

 

Sounds like the fan is shot. When it kicks on it puts an extreme load/resistance on the system. Check your fuses and see if it has the correct 10 amp fuse, I would suspect the fuse should be blowing which it apparently is not.

Test battery also, a weak battery can't power the bike at idle/low rpm. the stator doesnt kick into full capacity till around 6k rpm or so.

 

Thanks I will have to check the fuses and the battery. Is there anything else that it could be? The dealer told me that the carbs need to be cleaned but I'm not really sure that sounds right. Also I just got the bike last year and it has 23000 miles on it. Other than that problem it seems to run good but what things should I check to make sure the bike is safe to ride.

 

If it runs fine up till then, then the carbs are fine. Dealer's generally don't have a clue. Run some seafoam through it occasionally to help keep the carbs de-gunked. If the bike has over 23k then you will be coming due for a valve check pretty soon. 30k to be exact but if you dont know if it was done at 16k then it might be a good idea to check a little early. Anyways, the fan kicking on and causing the bike to die is definatly electrical, just gotta find out what/where/why. Good Luck.

 

I Checked the fuses, it's a 10 amp. The weird thing is that the bike runs fine when I disconnect the headlamp.

 

I have to reiterate checking the battery and the charging system. It sounds like its not putting out enough power to support everything.

 

I think jonld has probably emphasized it enough. There seem to be a quite a few of these this year - maybe it's because so many bikes are all getting to about that age.
I replaced the regulator/rectifier on both my previous CBR's - an F2 and an F3 - both of which had the same issues.

I'm pretty sure the reason we notice it when it's hot has nothing really to do with the heat itself - it's the fact that the fan is coming on. The fan and headlight on together draw too much current and the system can't handle it. Check the stator and the regulator/rectifier and ensure the battery is charging - that way when the revs are low, there's enough juice in the battery to provide the current necessary when the fan comes on.

 

+1 on a charging issues Check the R/R!

 

Agreed. When the fan comes on the bike isn't getting enough power to run the fan, headlight, and ignition components. If there's not enough power to be had they won't all three run.

 

Ok I took the bike to the shop and they said that the battery and the R/R are good. They also said that the stator was not up to specs and that this MIGHT be the reason for it not having enough power at idle. They said the stator was producing 66 volts AC and it was suppose to produce 75 volts Ac. Does anyone know what the Specs for the stator are suppose to be? Could this really be what's wrong with the bike?