Not to be a **** but...... Did you check the fuse? I had the same issue and went through everything only to notice that I overlooked the easiest thing to fix. But if your fan sounds like its coming on...?

 

How do you rigg the fan so you can manually turn the fan on/off

 

put the fan on a switch so you can cut it on earlier than the thermostat does if your worried about overheating

 

When you check your overflow tank have you been loosing coolant?
I recently found I was leaking a bit of coolant on occasion and had the recommendation to tighten all of my hose clamps. Most of them were fine, but some were loose with the worst offender being directly under the airbox. It was a PITA to tighten, but I have not seen any coolant since. This also caused issues with a lack of pressure in the radiator.

I have a '99 cbr 600

~KC

 

I've had the same problem. i've bled the radiator added new coolant/pump/thermostat and it still over heats in traffic even when the temperature is only 8 degees C like today!!!
i've admitted defeat and wired a manual fan switch up behind the left bar so i can switch it on as soon as i get near 90 degrees C and it never overheats now. it takes 15 mins max and can be put bk to standard just as quick
it seems like its a common problem. theres a lot of people asking about it on here

 

with the right tools and not having to remove the fairing this should take no longer than 15 minutes. its extremely simple but quite quite fiddly even with these tools.

you will need:-

soldering iron or crimping tool and connectors ( spades and m8 rings for grounding and battery connecting)
wire cutters
wire strippers
1mm cable
single pole switch

1. remove the left fairing (optional but makes it easier)

2. find the connector to the left of the fan with the blue/red wire and a black wire going to ground attached to it.

3.snip the blue/red wire from the underside leaving enough cable to reattach if you ever need to put it bk standard.

4. mask the top side and connect a 2 metre cable to the bottom side. colour is irrelevant.

5. on the bottom left hand side of the radiator is the thermostat switch with another black cable attachedd to it. pull this off the thermostat and connect to ground. ( i attached more cable on and mounted it to the frame behind the wing mirror but only because i couldn't get the groud screw undone on from the black cable mentioned in (2.)

6. take you're other added wire and run it up to a switch werever is best for you really. take the other side to the battery and its done.

if the wires are routed properly they cannot be seen.

do remember to switch it off though as it bypasses the ignition and will flatten the battery if the engine is not running.

using this method i can keep my bike at a constant 78 - 80 degrees C during all weather.

hope this helps

 

i will be doing this to my bike soon... i had the same problem and the fan would kick in once the bike is off, it would never kick in when the bike is on... thanks!!!

 

I had an identical problem where my bike overheated when in traffic....really annoying and I tried a number of things with no success. I took it to a mechanic and they had it fixed for under 200$, well worth it IMO. They said it was a fan wiring issue.....my fan always worked and kicked on at the correct times....I dont question it because my bike has worked fine ever since. Moral of the story is that sometimes its worth just paying a few bucks and not having the worry.

 

just so you know its the radiator temp swtich on the radiator that connects to the fan. If it gets a bit old, it kind of wears out and stops working. My friend just told me that happened to his r1 and thats what he had to replace. I just figured that out it sucks big time because its expensive to replaace... the easiest cheapest fix is to rig the fan tho

what i plan on doing on my bike is putting a swtich ON for city rididng, OFF for highway riding. I never really have to worry about it overheating when the wind is blowing cooling it down, its just stop and go traffic. My only concern is it killing the battery so i need to find a source to power it instead of directly to the battery

 

Hey gang,
Exactly the same problem, bike runs great on open road then overheats in stop start traffic, even in the garage the fan doesn't kick in until 3/4 up the temp gauge when it should kick in around the half way point.
I have replaced my old rad, new temp switch in post and I was planning on changing my old stat however as I was messing about installing the new rad I noticed that the fan (looking from the back) turned clockwise. I held a piece of paper in front of the rad and instead of the airflow being front to back I found that the fan was in fact blowing hot engine side air forward. Obviously in traffic on a hot day blowing hot air towards the rad isn't good so before you spend any more money / time on replacing parts maybe check the fan air flow direction.
I ride a 99 CBR600F4 and at some point over the years one of her owners has wired the fan incorrectly which probably led to her sale.
I have reversed the pos / neg wires on the fan and now the fan turns anti clockwise and now if I hold a piece of paper in front of the rad its pulled back towards the fan and for reasons that I don't understand the fan starts (in garage) just past the half way point on the gauge which is as it should be, hopefully I've cracked it and if not its certainly worth checking all the same.

Take it easy

Ray