I have a 99 f4 that runs perfectly fine except when the electric fan kicks on. Whenever the bike starts to get hot, a little over the halfway point on the temp gauge, and the fan kicks on the the bike will act like it wants to die, it is only noticable when at a stop light, and the rpms will keep dropping and coming back to normal idle over and over again. Today it died for the first time while doing this. The bike was originally used for stunting and I had to put it back together, all the fairings, re splice and put back all the gauges and all the wires. Thinking it could be a bad ground or something along those lines, i am going to tear it apart and redo all the wiring I had to splice awhile back over the winter. Was hoping for some tips or trouble shooting before I get into this thing. Thanks in advance for any help.

 

Bypass the fan relay to test and see if it tries to stall still. Not sure how to do this offhand. Maybe hook directly to battery while bike is running but don't electrocute yourself.

It sounds like it is having trouble running the fan. Could be a bad fan or a short somewhere or a bad relay or switch.

Could disconnect fan and see if is spins freely first. If it doen't spin then its time for a new fan.

Is it noisey when it kicks on (Louder than normal)?

 

Thanks for the reply. I haven't noticed it being louder than any other electric fan. I'm leaning towards it being a short somewhere, I'm going to start getting into this thing in the next few weeks so I'll let you know if I find this electrical bug.

 

It could be a number of things, but I recommend looking at he motor of the fan for increased draw (draining the system/killing your bike) or the charging system.

 

any luck on figuring out what was causing this problem mine just started doing the same thing....Its aggravating when in town cause very time you go to take off the bike stumbles over its self... help would be appreciated.

 

+1

 

I was also thinking that it might be a short. But first thing is first, Make sure your battery terminals are not loose. I have heard about people troubleshooting for HOURS just to find out that the connection to the battery was loose.

 

I have same problem with my 2000 Cbr 600 f4. As soon as it heats up and fan comes on the idle lowers and starts to stall. I wired fan switch to ground to keep fan on all the time and still has stalling issue. It is not a fan problem. With fan wired to run 24/7 it runs perfect till I am sitting at a light and it heats up. What could it be? I am at a lose. Please help. Temps outside are going to get hot and heat is the death of my bike at this point.

 

+1 on the getting hot soon, and I will also check my cables to see if they are loose. any more advice? thanks.

 

I have an F3 with the EXACT same issue. The bike begins to stall after running with the fan for a while. What I have found out is the battery is going dead. Think back to the the symptoms of an R/R. The bike stalls while trying to ride it and it stalls because there is no juice left in the battery.
So, if I am idling my way through traffic with the fan on for 10 to 15 minutes... the bike will begin to stall at lights. The stalling will eventually get bad enough to kill the bike if I continue idling through traffic. I've had to jump the bike and then raced for an open road where I could run the bike for a little while (5K+ RPMs) and this would would recharge the battery. I tested this by shutting down the bike and then restarting it. I've tested the battery and it failed a load test so I don't think I have an R/R issue. I haven't had the money to put in a new battery to see if it solves the problem though . The other thing to consider is, when idling... the bike isn't charging the battery. The bike will not begin to charge until the RPM's are higher than the idle.
But I think I have another issue too, the bike going from just above C to turning the fan on at one stop light. It's getting hot way too fast. Any ideas on that... feel free to PM suggestions... don't want to thread jack. The coolant is only a year old and it's full.