2002 Hornet 600 Overheating - Update, Thermostat Tested

[squishio]

Hi Guys

The wife's hornet has decided to start overheating, but I'm not sure why.

Yesterday she was riding it across London and the temp gauge went well into the red, she stopped, let it cool down and then carried on, and then did the same again shortly after due to the temp rising again.

This morning I changed the oil and also the coolant as it was due anyway, and I've just taken it out for a test ride, I was only out for about 15mins and the temp gauge was just under the red zone.
My ride was slow through town, but moving at all times.

However, the fan did not cut in at any point during (or after) my ride, I have checked the fuses and they're all in tact so it isn't that.

What should be checked next?

I would have expected that even without the fan kicking in, the bike should be able to keep itself reasonably cool in this 19* weather.

The radiator has the usual bent fins from stones kicking up, but nothing excessive, certainly plenty of airflow still going through.


I guess I'll need to put 12v straight to the fan to see if it works at all, it definitely was last week when I rode it as it tends to kick in when the temp gauge passes half way.

Other than that, could there be another more serious issue like a failed waterpump or something?

Cheers!
Rich

(I don't think it matters much, but but just in case it does, the engine is actually from a cbr600f, at least I believe it is judging by the engine number)
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Current - Hornet 600, Transalp 650, X140 Pit, GPZ400R
Past - SY125, GT250, GT650, CX400, CBF600, Bandit 600, SL1000, GT250

[RhynoCZ]

Stucked thermostat, the gauge itself, air in the system, faulty temp sensor, faulty fan, lean mixture.

Was the bike really hot?
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[squishio]

hotter than it usually is I think

Wife says it was cooking her legs, so certainly not its usual running temperature.
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Current - Hornet 600, Transalp 650, X140 Pit, GPZ400R
Past - SY125, GT250, GT650, CX400, CBF600, Bandit 600, SL1000, GT250

[instigator]

[RhynoCZ]

[MattEMulsion]

You need to get that fan working too don't forget!
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Yamaha YZF-R6

[squishio]

righto, so basically thermostat stays closed, so no coolant flows, correct?

Repair or replace?

One of these...
https://www.davidsilverspares.co.uk/CB600F2-HORNET-2002/part_71447/
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Current - Hornet 600, Transalp 650, X140 Pit, GPZ400R
Past - SY125, GT250, GT650, CX400, CBF600, Bandit 600, SL1000, GT250

[moonzoomer]

To test remove stat, put in pot of cold water and place on stove, once the water has just started to boil the stat should open, if it stays closed it is knackered. Use the same test for the electrical fan stat and check for closed circuit once the stat has reached temp using an ohm meter.

[squishio]

I think the thermostat is fine...

I removed it, and stuck it in a pot and heated it up, it opened at around 85*C and closed at around that temp when cooling down...

Boiling...
https://i.imgur.com/5WRCni8.jpg

Open...
https://i.imgur.com/WlhElbN.jpg

Open...
https://i.imgur.com/U0bMDfK.jpg

Closing...
https://i.imgur.com/ZlkVePY.jpg

I've only just done this, so have not yet fitted it back onto the bike/gone for test ride, but I assume the thermostat is fine as it did exactly what it was supposed to do at (as far as I know) almost exactly the temperatures it's supposed to do it at.

I know it wouldn't be ideal as the engine will take longer to warm up, but could I leave the thermostat out, test ride and see if the temp rises as before?
It looks like the cover for the thermostat goes back on regardless of it being in place or not.
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Current - Hornet 600, Transalp 650, X140 Pit, GPZ400R
Past - SY125, GT250, GT650, CX400, CBF600, Bandit 600, SL1000, GT250

[prawny1]

Honda usually wire the fan via the parking light part of the ignition switch with it's own fuse so that if you park up with the fan on and put the ignition in park the fan stays running until the bike cools even with the key out.

Test the stat switch by shorting it to ground to see if the fan comes on if it doesn't Check if the park light works, that will tell you if the ignition is powering the circuit.

If you have no park light either you probably have a blown fuse if the park light does work it's bad wiring somewhere along the line or a dead fan.
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hellkat wrote:

Some people are only alive cos its against the law to kill them.

[squishio]

I shall do that tomorrow

However, regardless of the fan working or not, I don't think the bike should have gotten as hot as it did, considering it wasn't a particularly hot day and I wasn't stuck in traffic / sitting still...
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Current - Hornet 600, Transalp 650, X140 Pit, GPZ400R
Past - SY125, GT250, GT650, CX400, CBF600, Bandit 600, SL1000, GT250

[RhynoCZ]

[instigator]

[squishio]

Will check out the fan tonight and update accordingly, thanks guys.
____________________
Current - Hornet 600, Transalp 650, X140 Pit, GPZ400R
Past - SY125, GT250, GT650, CX400, CBF600, Bandit 600, SL1000, GT250