Engine coolant temperature

[Longdog Cymru]

Nothing quite like opening a can of worms is there, so here we go!
One of the things I notice about flashed ECUs is lowering the temperature that the cooling fan kicks in. Does anyone have a definitive reason why lowering the temperature that the cooling fan kicks in is a beneficial given that Yamaha have done quite a lot of research to arrive at the temperature that they have. Modern engines and oils should take this in their stride without degrading or any detrimental effects, so it would be interesting to hear if anyone has a real reason for this.

 

[Cantab]

It is your choice to lower the temp when flashing or leave stock.

I dont really know but i would think any lowering of the temp would enhance oil/coolant life some what.

 

[jbrown]

Anthony originally changed the temperature to make it easy to tell the ECU had been flashed.

 

[Gerard]

I would like to think the engine has been manufactured to specific machining tolerances and runs in its optimum condition when a certain temperature has been reached. It is for that reason i would not change the kick-in temperature. That's why i never developed the habit of first warming the engine by idling it for a couple minutes but take off straight away without thrashing it.

 

[Sierra1]

. . . . That's why i never developed the habit of first warming the engine by idling it for a couple minutes but take off straight away without thrashing it.

"They" have been saying that for years. Modern vehicles don't need the warm up they used to. I think it has to do with the cats. (converter) The closer they are to the motor, the faster the motor gets to proper operating temperature. Once they get to proper operating temp, they use less fuel. That's one of the things that irk me about remote starting. People letting cars get warm/cool while there still in the house.

 

[fac191]

I was told the gearbox heats the engine quicker so start up and get moving just keep the revs down.

 

[lund]

Modern motors today for efficiency and long life need to run HOT, cold running motors have much higher wear and are less fuel efficient.
Back in the 70s and 80s most motors ran 160deg to 180deg at most. Today modern motor run at minimum 180deg and average 200-220deg is normal.
This includes diesel.
Allowing the motor to warm up on a cold day is essentially not necessary with today's modern fuel injected engine. Pretty much all manufactures say it may be driven after a minute or two from startup.
With the ECU's the engine is protected till the proper temperatures are reached, this includes our bikes.
The reason behind letting the motor warm up had to do with carburetors. When cold the carburetor ran on its choke plate at a high idle to allow it to reach operating temperature quicker without stalling. This caused all kinds of runnability issues, thank goodness for EFI that essentially cure this problem.
As for lowering the temperature the fan comes on would only be beneficial in the most extreme temperatures, like off roading or heavy traffic. Yamaha S10 thermostat is set to open at 160deg and is fully open at 180deg.
While the fan does not come on till the temps reach around 210deg with the OE programing. The 1200 can run hard all day at well over the 200deg mark and never overheat.
From experience I have had mine run 230deg from the radiator being plugged with mud in 30+deg temp on an off road adventure with no issues.

 

[Longdog Cymru]

I was told the gearbox heats the engine quicker so start up and get moving just keep the revs down.

Yep! An engine under load warms up quicker and the cat needs heat to operates correctly, ie it burns off the exhaust gases and produces a cleaner exhaust.

 

[fac191]

I beleieve finer tolerances due to better engineering mean you dont need to do it. ie piston slap was a reason to warm it up first.

 

[Cantab]

I would like to think the engine has been manufactured to specific machining tolerances and runs in its optimum condition when a certain temperature has been reached. It is for that reason i would not change the kick-in temperature. That's why i never developed the habit of first warming the engine by idling it for a couple minutes but take off straight away without thrashing it.

The S10 is the only bike ive let mildly warm up that is around 50degC(yip it does drop temp when bike is first upright off stand) , i start bike push bike out of garage put on skid lid gloves on close garage ride off, i find if i just get on and ride it and get to the stop sign down the road when i throttle off it still wants to charge ahead not slow down, this IS only till around 65-75deg ish then normal decel.
If that makes sense

 

[MattR]

My reason for having the fan kick in 5c earlier:
In the UK my bike runs at between 75c and 85c. It only ever gets hot enough to switch the fan on when standing still.
The fan does not control the normal engine operating temp, the thermostat does. The thermostat keeps my engine at around 75c which is the normal design operating temp. The fan only cuts in to prevent overheating. Therefore by lowering the fan temp by 5c I can get the fan cutting in just before boiling point.


Sent from my iPhone using Tapatalk

 

[cyclemike4]

I would like mine to come on earlier than it does. I am pretty sure my fan doesn't kick on till about 220 and turn off at 210. It seems these Japan beer cans can handle high temps and be ok though. When I first bought this bike I thought it was going to melt down. The fan would not and could not cool it down. If I rode slow I was seeing temperatures very close to 240 degrees. Not real slow I was riding along at 35 miles per hour. The only way it would cool down was to get some speed and air moving. I guess engine break in and messing with the bleed screws on the throttle bodies got it down. If it is cold out ( 30 degrees F and lower) and the bike has been out all day in the weather I will let it warm up a bit. Usually not long though. I can't say that it is any better than my bikes with carbs though. They started easier than this one does in the cold and warmed up quicker. I am glad it quit running those crazy temperatures. I really don't think it would have lasted doing that.