Hi all,

I've been diagnosing an overheating problem on a CBR600 FX for the past week or so, mostly using suggestions from here and other forums.

I've got a question for you. I need to replace the Rad Fan (definitely) and possibly the Fan switch and radiator on the bike. The question is: Which model CBR's can I pinch parts from? I've phoned Honda who told me 1997-2003 CBR600F's are virtually identical, however is there a wider range? Can I take a rad & fan say from a CBR600 RR7?

Thanks!

Andrew

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Now - to give something back to the forum, heres the steps I took to diagnose (and almost solve) my heating problem.

Testing / Diagnosis

1. Centre stand the bike with fairings off. Drain coolant reserve tank. Open rad cap
2. Start bike. Squeeze side tubes, move bike from side to side, rev throttle to "burp" the coolant system. Level goes down as you rev throttle. Bubbles come out of system.
3. Top up with coolant, rad cap back on
4. Idle for 30 mins. Let it get warm (half way on temp gauge)
5. When warm, rev it. 4k-6k RPM. Fan should come on over half way on the gauge

-- At this point if revved hard my bike gets hot, coolant boils, the rad cap gives and coolant overflows into the reserve tank

I've replaced the thermostat and rad cap as they were both faulty. Now I've noticed this. When the bike is hot, the fan seizes up. It correctly cuts in at 1/2 way but if the thermometer gets to 3/4 heat the bearings squeek on the fan and it seizes up. Definitely need a new fan.

So faulty parts on my bike so far were 0.9 bar rad cap giving too early, replaced with stock 1.1 bar cap. Thermostat was not opening correctly. Replaced that. Now lastly fan cuts in right but as the bike gets hot it often stops!

 

Yeah, definitly sounds like you have a bad fan for sure. I'm looking at doing a full system flush with system cleaner cause mine sat for about a year and a half without the bike running. My fan seems to kick on more often than I remember it doing. I'm thinking I just don't have good flow of coolant.

 

Right, I ordered a new fan from a breakers yard, but when it arrives it doesnt fit? Despite being off a CBR 600 FX (same as mine).

Anyway long story short, I hotwired the fan by putting a switch in to override it. I drilled a hole in the plastic below the left handlebar and installed a toggle switch with waterproof cover. I wired it to ground one side (a screw on the fan to the radiator) and spliced to the wire that goes into the thermostatic switch the other side. Result is, when the bike is on, flick the switch, fan comes on.

Now my fan blows loads of air when the bike is cool so I took her for a spin. Funnilly enough after a long ride around the countryside the fan is spinning very slowly, if at all even with the override switch. It seizes up again. Let the bike cool and the override switch works again.

So back to the drawing board. I need a new fan (still). Either the motor / bearing seizes when the bike gets hot, or the electrics are disconnecting the fan only when hot.

Still working on this ... At least I know where the problem lies now though!

 

Hi did you ever sort this?
I have exactly the same problem!

 

Yeah I took it to a local bike garage which found the right fan and fitted it.

The problem was the old fan was somehow warped so when it heated up, it got jammed and stopped spinning. The new fan did the trick and kept the bike from overheating.