CBR600fm got a bit hot today

[rainman]

Have fun, I'll also be in maintenance mode, pulling my new tank off and redoing all the hoses, assuming I can find some suitable hose clamps at Repco or Supa Cheap. Leaking tank = bad idea!

[rainman]

i'll have a go tomorrow

So, how'd you get on?

I only had to redo the tank once because I didn't tighten the clamps properly enough and it still leaked after I filled it up

[jamiey]

I've kinda been sidelined, trivial stuff like having to go to work and kids!! I'll let you know as soon as I pick up my spanners!! Did speak to a guy today at econohonda (good on those boys, always helpful and have cheap parts) - got a new thermo switch on its way for $40 (130 at honda), so gonna replace that too while im in there, i'll keep you posted on progress...........

[vifferman]

You said that five minutes of sitting after running the bike will get the temp into the red - that sounds about normal. The engines heat up pretty quickly when sitting idling. However, the fan should've kicked in.
If the fan switch is like that on most Hondas, to make it go it's just a case of turning the key on and shorting the wire ('earth tag') to ground (some part of the frame or the engine). However, if it doesn't go, that doesn't necessarily mean it's the fan - it may not be getting power to it.
If there's an air lock in the cooling system, that could cause the bike to overheat. I don't know how that's dealt to on the 600, but on the VFR it's a case of taking the radiator cap off, running the engine (but NOT when the bike's really hot!) and squeezing the hoses to burp air out, while toping up the radiator.
If/when the waterpump carks it, it's usually signalled by a leak from the housing (and corrresponding puddle of coolant under the bike). The pumps usually work fine until the seals go, and this is handily indicated by a weep hole built into the housing.
The thermostat's main function is to allow the engine to warm up by stopping coolant circulating until the engine has some heat in it, and to pressurise the cooling system to stop the coolant boiling off. If it's defective, it will either cause the engine to run too cool in cold weather, or will provide insufficient pressure, causing the coolant to be lost (which will cause the engine to overheat).
Last point: you haven't actually said anywhere if the coolant level is fine - the radiator should be full, and the overflow/expansion bottle half full.

[Max Preload]

If the fan switch is like that on most Hondas, to make it go it's just a case of turning the key on and shorting the wire ('earth tag') to ground (some part of the frame or the engine). However, if it doesn't go, that doesn't necessarily mean it's the fan - it may not be getting power to it.

Like he said, earth the wire from the fan thermo switch if it's a single wire, but if there are 2 wires short them together.

If you want a hand PM me.

[NOMIS]

Hi Everyone,
I took my 1991CBR600fm for a little mid winter run today as the sun was shining and i had a day off work - just perfect!!
I noticed when sat in traffic that the temp gauge had risen to almost on the red, luckily I was away riding again with plenty of getting into the radiator before the gauge got right upto the red.
When I got home I left it running on the drive for a while and the same thing, needle (slowly crept up towards hot) so turned it off before it overheated.

I'm new to the forum here so thought i'd try and seek some advice before going out wasting money on bits I don't need

what would be the first thing to rule out?? thermostat perhaps?? fan switch?? or just a simple new lot of coolant - anyone know any simple diagnostic tests to determine the cause, or even is getting to the top of the normal temp range usual with these bikes?? Its my first CBR so not too sure, its fine when i'm riding, no problems whatsoever and the temp is always normal, the problem is after about 5 minutes when stood still

Cheers

Jamie

If you dont have a clue and want to do it your self start with the elimination process. coolant .. and make your way towards other things. hopefully something simple and habn't cracked the gasket or anything

[Max Preload]

If you dont have a clue and want to do it your self start with the elimination process. coolant .. and make your way towards other things. hopefully something simple and habn't cracked the gasket or anything

The fact the temperature gauge registers the overheating is a pretty sure indication of sufficient coolant - senders don't work well in steam. Besides, one would assume that coolant level is the first thing poster #1 would have checked.

[NOMIS]

The fact the temperature gauge registers the overheating is a pretty sure indication of sufficient coolant - senders don't work well in steam. Besides, one would assume that coolant level is the first thing poster #1 would have checked.

Correct you are , and yes you would hope so wouldnt you.

[jamiey]

Thanks guys, loads of helpful advice, but alas another day spent in the garage to no avail, coolant is fine and ive replaced the fan switch, ran the bike for a bit then let it stand and it took about 10 mins to get near the red (pretty normal i'm sure). I let it get into the red mark on the temp gauge - still no fan!!! So i turned it off to prevent any damage. Im not too bothered as its ok under normal conditions and i tend not too sit in traffic anyway, its just bugging me now and i will have to get it sorted before those long hot summer runs (seem far far away at the moment). Might just bite the bullet and take it in somewhere..............

[jamiey]

Just done viffermans quick test on the fan (thanks) and it works fine came on straightaway, so fan works, coolant is good, new fanswitch, next??

[Max Preload]

Did speak to a guy today at econohonda (good on those boys, always helpful and have cheap parts) - got a new thermo switch on its way for $40 (130 at honda), so gonna replace that too while im in there, i'll keep you posted on progress...........

Just done viffermans quick test on the fan (thanks) and it works fine came on straightaway, so fan works, coolant is good, new fanswitch, next??

I'm confused. From what I understand you've fitted the 'new' fan switch from Econohonda and it still doesn't oerate the fan automatically? You didn't put thread tape on the swtich thread, did you? You can't do that with a single wire system (and don't need to on a thermo switch anyway - they're a parallel thread with a o-ring generally). A single wire system relies on grounding through the thread to the radiator to the chassis.

When you earthed the fan switch wire which then started the fan, where did you earth it - radiator or frame? Does the fan work when you earth the wire through the thread on the radiator? Check for continuity between the radiator and the frame with a multimeter set to resistance.

[jamiey]

I earthed the fan to the frame, no thread tape on the switch.........

[Max Preload]

I earthed the fan to the frame, no thread tape on the switch.........

Does the fan work when you earth the wire through the thread on the radiator? Check for continuity between the radiator and the frame with a multimeter set to resistance.

You're making it really difficult to establish anything concrete by answering so selectively and briefly.

[jamiey]

Sorry Max, ok here goes. The fan works when i ground it to the frame, but when i run the temprature up to almost the red i'm getting no ground through the thermoswitch, therefore the fan isnt coming on automatically. I tried grounding the fan by touching it against the radiator but nothing happened

[Max Preload]

If you're sure you got a good connection on the radiator (not a painted bit) and the fan still failed to operate, you need to check for continuity between the radiator and the frame. Do you have a multimeter?