I took the bike out last night for bike night at a local restaurant/bar. The only thing I had changed on the bike before I left was I reattached the front fender. The bike seemed to run just fine there but when I returned to my garage the temp was sitting at 236F, there wasn't any traffic and 80% of the ride was on the interstate. I think it has something to do with me hitting the rev limiter for fun 4-5 times at bike night. The cooling fan wasn't engaging at 225 as usual, I figured maybe a fuse blew and I let it idle too long. Today I took it out on the interstate and was having overheating issues. Wide open roads traveling at 65-85mph and could not get the temp below 208F, at one point it dropped to 193 with high winds, and 180 when i went through a puddle of water. When I am in traffic it over heats very fast, normally at most it raises about 1 degree every second or two in traffic until 225 then fans down to 220. Now it's acting normal until 176F on the dot, then the temp drops to 168F and will go up a degree then down one like it can't decide until it hits high 170's-180. Once it hit's 180 in traffic it will start jumping sometimes 3 degrees in 1-2 seconds. It overheated (252F) for the first time in it's life today after only a few minutes in traffic and it has to be going at least 50mph to begin cooling back down. I took the radiator cap off and it was full, I left it off and ran the engine to check for air bubbles but there were none, and I noticed that the coolant seemed to be circulating/changing levels when I revved the engine. I noticed some small black specs floating about in the coolant as I watched it through the engine cap, and saw them in the reservoir which was full also.
I find it strange that I am having this sudden overheating issue AND my cooling fan decided to stop switching on. I checked the fuse, connectors, and made sure it could spin freely. I still think hitting the rev limiter back to back did something but idk how that could affect both the cooling system and the fan. What should I check for first to keep this from being a nightmare teardown? Is there more than one coolant impeller on the F4i? (I thought I noticed 2) Does this sound like a thermostat issue, stuck coolant impeller, what's with the black specs, and could the cooling fan be related the overheating issue other than being electrical? The temp sensor is working fine why not the fan? Thanks a ton for any help! I just drove 140 miles through the worst thunder/electrical storm I've ever seen. I sat under the most bridges of my life and my *** hurts!

 

Sounds like thermostat issue.

Before going there, check:
1. The 20A fan fuse is blown
2. Whether the fan is really can be turned on by jumping it
https://cbrforum.com/forum/stickies-...ng-fan-122988/

It could be the thermo switch
https://cbrforum.com/forum/cbr-600f4...lready-114554/
37760-MT2-003 SWITCH ASSY., THERMO $40.48

Good luck

 

Also check there's no rocks or road grime blocking the fan from spinning, this was the problem on my bike when I first bought it and the fan wouldn't kick on.

 

Thanks for the tips, the fan spins freely but I wired it straight to the battery and got nothing. Although I'm unsure as to how the fan mechanism works when it turns on. I just gave the blue/red (I think) wire 12v, and tried grounding the black even though I tested the continuity and it was fine. Tried + and - direct to fan still nothing. I removed all of my fairings and the overheating issue is gone. It worries me that I have to strip my bike so it'll run at normal temps. I have engine ice, 50/50 coolant, it normally ran at a constant 167F. So it runs fine for now but I don't know what to do if I buy new fairings and it overheats too much. Might go streetfighter with it.

 

so your fan is still not working but you plan to still ride it anyway? good luck with your warped cylinder head goals for 2013, if it is not already.