Engine overcooling.

Hi, I have a 2004 SV 650, which has a problem with the temperature reading.
It only gives a low reading (20-28 degrees), no matter how hot it is.
I have tryed fitting a new temperature sensor to the thermostat housing, but it gives the exact same reading.
Has anyone experienced this before, or have any ideas on what could be wrong???
Cheers, Carl.

[Sid Squid]

Do you mean that the gauge always reads 20-28 degrees? Even when you turn the bike on from cold too? If yes, then the gauge is suspect. If no then have you checked the thermostat itself? Overcooling is very often caused by a failed open 'stat.
As a very rough rule of thumb test try feeling the cooling hoses - are they hot or do they stay cool. If they get hot then the reading is wrong, if they stay cool then the cooling system is working uncontrolled. If the reading is wrong then you'll need to test the readout of the gauge, if the cooling system is uncontrolled then the 'stat is your first and most obvious suspect.

HI, no it reads -- for a while, the a minute or so the thermostat switches, allowing the water to the rad it reads around 22, and very slowly gets towards 30.
I believe the thermostats are designed to switch at 50 degrees, so the reading is miles out.
It doesn't have a cooling fan fitted (its a race bike).

Does this mean its likely to be the clocks??

Cheers, Carl

[Sid Squid]

The thermostat should be closed until it reaches 88 degrees and fuly open at over 100 degrees.

I think yours has failed. They are designed to fail open so that engine damage through overheating will not occur, when that happens overcooling is the usual result.

[punyXpress]

If it's a race bike are you sure there's a 'stat in there at all?
Easy to check it on kitchen stove buy don't point Mrs Carl90 my way if she catches you at it!

Does overcooling mean more engine wear?

[Sid Squid]

Yes, amongst other problems. Essentially the oil won't be working right, the various bits of engine are sized to fit together when hot so don't do so quite as well when not at full temperature, and the engine won't function at full efficiency. A fuel injected engine can run very oddly if it overcools, this is greatly dpendant on the physical location of sensors.

Im pretty sure it does open, as the rad will stay stone cold for a fair while until it suddenly gets hot, which i presume is the thermostat opening.

Oh i should have said, this is a tick over, so with no air passing through the rad to cool it down.
Cheers, Carl

If it's getting hot then it must be the electrics (assuming hot is more than 28 degrees). Depending on the type of probe (sensor) a bit of corrosion or crud on a terminal could increase the resistance to the computer and show an incorrect reading.

You could always plug into a friends clocks to try and rule those out.