Warm/hot running Curvy

My 99 naked curvy seems to be running pretty hot to me - am going to check the fan motor and switch operation at the weekend, as I can't recall ever noticing the fan being on. However, I'm not sure if there's a problem, or I'm just being over sensitive(!). I've recently started a 20 minute commute in moderate - heavy traffic with much more queueing/filtering than my previous run to work. By the end of this, the frame is warm to the touch, and the cylinders are hot, so that you can only touch them for a second or two without getting burnt(I imagine - haven't kept my fingers there long enough to test this!). Most of my previous riding was a pretty clear 15 min commute, or higher speed riding on twisties/A roads, and I'm pretty sure it never got this warm. Obviously the lack of air flow over the radiator will result in warmer running, but would be grateful if anyone knows if this kind of temperature is normal!
Cheers
Birdie

I have mostly used my curvy for fun blasts.

Last friday night went into C London and noticed the bike gets considerably hotter.

If you havent noticed anything wrong as such, I wouldnt worry too much. Just my 2p.

[Biker Biggles]

If the bike is getting noticeably hot in traffic the fan should be coming on.If its not you can check the fan itself by connecting the wires that go to the temp sensor bung thing in the rad.The fan should then run proving it works and the problem is likely to be the sensor.

Fuel consumption is a bit rocky, but its overdue new plugs, which I've just ordered, and I discovered the fuel tap vacuum hose was perished and leaking slightly ( replaced today)- not sure what effect that would have had. Planning some service/TLC at half term (am a teacher), but thats 3 weeks away yet...
Cheers mate! Any further wisdom/experience/thoughts from anyone else gratefully received.

[yorkie_chris]

Engines generally get hot in use

Generally it is painful to keep your hands on the cylinders of a hot engine. The coolant is designed to be at 80 degrees+.

Thanks Chris - :P guess I asked for that one! After an extra long run filtering/queuing in heavy traffic today the fan still hadn't kicked in - pretty sure thats the prob.

[yorkie_chris]

I do not think you have any problem. Feel free to test fan circuit for good health though.


The curvy is pretty well cooled, it's rare the fan kicks in.

If in doubt then fill the rad with water not coolant and point the breather pipe over the clocks or somewhere you can see it... if it starts boiling over you have a problem. 99% of time there is no problem.

That is me talking who used tiny splash of antifreeze in water, riding all summer in all conditions with tuned engine and no fan fitted at all!

Normal operating temp is 95deg, and yes the frame gets hot too as its bolted direct to the engine. I certainly wouldnt expect to be able to touch the cylinders.

To check the fan, go for a run to get it warmed up and when you get back just let it tick over for several minutes. The fan should kick in before the over temp warning light comes on.

If like mine, the fan didnt kick in and the light comes on. Shut it off straight away.

The connections for the fan are easy to get to. Lift the tank and they are about 12" down from the headstock covered by a rubber boot on the right hand side. Check they are all plugged in (turns out the reason mine didnt work was that the fan switch was unplugged!). If they are, then while the bike is still hot unplug the switch and check the two wires are connected with a multimeter. If they are OK, then plug it back in, then unplug the fan power and see if you have 12 volts with the ignition on. If you dont then you need to trace that wiring back and find out what the problem is from there. If you do have 12v then the fan motors probably stuck.

Originally Posted by yorkie_chris

I do not think you have any problem. Feel free to test fan circuit for good health though.
The curvy is pretty well cooled, it's rare the fan kicks in.

I have to agree there i've never noticed the fan comming on when i'm out on mine and the temperature lights also doesnt seam to come on, i have just put it down to cold weather keeping the bike cool myself though.

ace cafe toy run didnt get my fan on, when the ducatis were killing the engines yet leaving there fans running to cool the engine down some more.
i do a half hour commute in heavy rush hour traffic and still never had the fan on, ever