Engine Temp too low

Hey guys my first post here but I frequently read the forums and love it for all its information. Recently I've run into a stump with my new 1987 vfr700f2. I finally was able to clean out the carbs after it was sitting for 5 years in a heated garage and was able to fire it on the third attempt. However, after letting it run for about 10-15mins I noticed the temperature gauge never passed the Cold line and the radiator fan never kicked in. The radiator was very hot and untouchable and the tubes leading to the water pump and thermostat were warm as well. Now when I added coolant I filled it to the top and tried to burping it. However, the coolant level never went down. I started it up again with the radiator cap off and I didn't notice any coolant movement.

First I tested the temperature gauge and it worked properly. I then proceeded to check the fan from thermostatic switch and it ran properly. Finally I took out the thermostat and it wasn't stuck open. I then tested it by heating it in water and it opened and closed properly.

Now since the coolant system never really burped properly I believe there is air in the system, but since air is a poor conductor of heat wouldn't this cause my bike to overheat instead of running cold? Sorry for the long post guys but I tried to give you as much information as possible. Thanks for all your help! :biggrin:

 

eh ten or fifteen minutes isnt really enough time, my 86 neddle doesnt even move untiml the bikes been running for at least 20 minutes after a half hour of so the fan MAY kick in...take it for a ride around the block and get it some alternating RPMs other than idle then check your guage....it will move then...

 

Did the gauge move at all??

If yes then Crusty is probably right

If no then maybe the temp sensor is in the air lock you think you might have?? That would work in the way you describe - but the opposite way around.

 

The gauge did not move at all. I'm going to flush the system after work today and try it again but run it a little bit longer and I will get back to you guys. Tris, this is whats stumping me because it should be the opposite effect on the gauge but hopefully a flush and refill will do the trick. Thanks for your quick replies!

 

You could be too hot and not know it: If the cooling system is not almost 100% full then the temp sensor, way up top next to the thermostat, will not be immersed in liquid and will give inaccurate or spurious readings, since it needs to be covered by liquid coolant, not air, see?

Anytime the coolant is drained it takes a short time running at speed to bring all the air to the top. So ride it easy a little, bring it back, let it cool down, open rad cap and fill right to top......You need to be worried if coolant seems to disappear.

Proper operation of the gauge can be determined by VERY, VERY briefly touching the wire going to the temp sensor to GROUND briefly!!!! The gauge will show go full-scale reading.
Checking the sensor itself is a different deal.

Under normal conditions in northern climes temp guage won't reach much above bottom of scale in less that 20 minutes of riding. Normal temp after full warmup while cruising at moderate speed on OPEN road is less than 1/2 scale.


If you want to do some more intense investigation, remove the cover on the waterpump ( very easy) and look around for blockage or a loose impellor.

 

Update: Well good news I flushed the radiator for about 10mins. A decent amount of eroded like material came out. After filling it up with coolant and with a few burps it is now running properly. The gauge went up slowly so you were dead on Crusty. Thanks for all the replies and help guys I'm pretty sure it was an air pocket and a combination of not running it long enough.