We might have had this before, but I'll take a chance as I'm in a rush and haven't got time to search (sorry all!)

When I fire up my bike, the fan is on straight away. Is this usual? I can't remember, as I'm usually on top (although not for long, to be fair!) and don't recall ever noticing one way or the other before?

Cheers

KB.

KB-

The fan should not switch on until the engine is hot. This is the opposite of the usual problem, which is the fan will not run at all or will not start until spun by hand.

There are 2 possibilities to your problem. Either the temperature switch has failed with the contacts closed or there is a short circuit in the wiring. I don't know the history of your bike, but sometimes people connect the two leads going to the temperature switch together as a temporary fix for a bad switch.

In warm weather, having the fan run all the time will probably not hurt anything. just be sure you allow the engine to warm up fully before you start revving it hard. I would go ahead and take care of it as soon as you can though.

the only risks you face of having you fan run all of the time is of siezing it from cold if you dont warm it up properly, or simply burning the motor out in the fan, however this wont happen for a while yet (i guess, depends on how mich the bike has been ridden)

If you put a continuity meter on both terminals of your thermostat when cold, and get a circuit, you need a thermostat.

Well, I ride about once a month these days, so the fan won't get that much stick relatively speaking.

If you've read my other blurb on the main boards you'll see if I just had it in for some tidy up jobs, and they didn't mention the fan being dicky on the job sheet, but I'll keep my eye on it none the less.

Thanks.

PS - Whats a continuity meter?!?!? I'm rubbish at technical stuff!! I know how the metal bits work pretty much, but the wiry plasticy electrical bits - I know nowt!!!

Cheers

KB.

Had a similar problem with my Fantic, It turned out that the switch had actually broken. These thermostatic switch's usually work with a small plate like a diafram. Under normal circumstances the switch is held open by the diafram and when the bike is hot the diafram clicks the switch into the closed position. However this also means that if the switch gets a bang and breaks, the diafram is now not working and the switch stays in the normally closed position. ( Commonly known as fail safe.)

PS - Whats a continuity meter?!?!?  I'm rubbish at technical stuff!!  I know how the metal bits work pretty much, but the wiry plasticy electrical bits - I know nowt!!!

Cheers

KB.

If you have a meter that checks voltage, etc (if not, they can be had very cheaply), it will have a mode for continuity, meaning "can electricity flow through this thing that I'm touching with these two probes?"

If switch AB is open A / B you'll have no continuity between A and B.

If it's closed A--B you'll have continuity between A and B because they're connected.

So, if there's a wire with power on A and a wire on B that goes to your fan, your fan will be off until the thermostat heats up, the connection closes, and it allows power to pass through to the fan.

Fortunately, these things are usually made so the least dangerous thing happens if they crap out--meaning, if it breaks, it'll keep your fan on rather than keeping it off.

Hiya Kinky! Chris had this problem on his REV50, and that was the thermostat. I think the part is the same on both bikes and cost