Overheating mark 3 !!!

[cargo]

Just throw the thermostat into the bin you don't need it.....................................

Are you sure that you have filled the rad properly........................and that theres no air in there.
I assume you have not modified the rad to lower it in any way ?
How clean is the rad externally is there a good air flow through it when you are riding the bike ?
Is the water pump actually pumping ?

In my experience ZXR run on the cool side. I've never heard the fan cut in on a road one and my race bike just don't have a fan. My point is that the bike should run at a reasonable temp regardless of the fan working or not the only time you should see the fan running is if you are going very slow in heavy traffic say.

Are all you hoses properrly connected in the right place ?

IF the HG was gone you'd be losing water.................. try a pressure test on the cooling system see if theres a leak

Also there would be a loss of performance of the HG was gone.

9 time out of 10 it's something simple.

[reds]

thanks for all the input guys

right - got thermostat out tonight (who on gods green earth puts a bolt in such a stupid place !) was a right bugger.

thermo has a bit of rust on it - dumped it into a pot of boiling water and i didnt see anything change - is it a miniscule amount that it opens or should it be noticeable ?

cargo - rads not modified, and did a full flush on it the other day, when drained it again today coolant mixture came out clear, without any nastiness in it, so dont think its blocked

also if i think that the thermostat might be dud (as i couldnt see it open) is it ok to run without one ? does it just mean i have to leave the bike to idel for a few mins before i go out on it - so that it warms up ok ???

thanks again for all the input guys - would like to get a couple more months out of it (as the one way system to my work is currently closed for 12 weeks, meaning massive traffic and a 10 mile detour everyday) before a big winter, strip and rebuild

[bendog66]

you should let it warm up regardless

[cargo]

All a thermostat does is speed up the warming process once the bike is warm it has no function......................throw it away.

Having a good flow of water through the rad is good but equally it must flow air as well.........................
I don't know what age your bike or rad is but you need to check does it actually allow a flow or air through it. Hold it so you can see through it or not as the case may be

Cillit bang is good for cleaning rads externally

[bendog66]

9 time out of 10 it's something simple.

you have checked the fuse for the fan, haven't you? and whilst you're at it make sure the wire from the fan switch hasn't been touching your downpipes and melted it

[reds]

thanks guys,

spoke to cradley this a.m - the thermostat is def dud, as they said i should be able to see it opening.

i assume that this would therefore mean that the coolant mixture was going through the rad fine, and was being pumped up to the engine, BUT then it wasnt getting past the thermostat - hence why the bike was running hot / mixture was backing up into the overflow (the thermo i took out doesnt even open a fraction)

i would also assume that this is why i only managed to get 1 litre of mixture into the system as opposed to the 2.3 that the manual states (as it wasnt going into the engine itself, as it was blocked from doing so by the thermostat) - so quite worryingly the only liquid in the engine to cool it, would have been the stuff that had gone down the pipe to the left of the filler cap, when i was filling it up ? does this sound right / make sense ?

Cargo - will remove rad and have a look through it / general clean, it is an 89 H model, so its old - will also check wires, but pretty sure they are all in tact - fan works fine when it is shorted, just not when engine is getting too hot

[cargo]

The bike should run fine with no fan the fan should only cut in when it gets hot in slow traffic or waiting at lights on a hot day.
Anyway didn't you say that one side of your rad was much cooler than the other...............the fan may well not have cut in because the sensor switch wasn't getting hot enough

You bike is 20 years old...................thats very possible 20 years of road crud encrusted into your rad...................It will need cleaned..................

Since it now seems you had a faulty thermostat...................your hot running problems will soon be gone...................

[reds]

nice one, cheers cargo - will get rad off and cleaned tonight, possibly pop a new thermo in, or just run it without (how much longer are we talking about leaving it to warm up without a thermostat ?)

[reds]

thanks for all the input guys - put 100 miles on the bike this weekend, no worries

looks like it was the thermostat causing the issues, popped a new one in, and havent goneout of the two white marks (except in very heavy traffic, but only a mil or two out) - think that he rad flush / clean helped out too