Strange engine temperature reading

[PTrouw]

I had a drive of half an hour, outside temperature 14 degrees Celcius, so not that warm. Engine temperature reading about 78, as usual. But just now while parking and running idle, the temperature reading went up quickly in steps of 2 degrees, until it was hitting 100 and the fan kicked in.

But the engine was not "overheating" Seems like it got an incorrect reading from a sensor.

Any idea which sensor and where it is located?

And other ideas on this?

[Ray Ride4life]

Big mistake many people make is reading the temperature in the display as engine temperature.
Most motorcycles and also cars display the temperature of the coolant and in a few cases the oil temperature but never the engine temperature, however the oil temperature will come pretty close.
I never understood why they all use the coolant which fluctuates like crazy and is a lot faster at temperature than the oil.
That is also the reason you never should go full power when the display says it's at the right temperature because it is not the case. The coolant has a bypass to get at temperature as fast as possible.
The coolant runs through the radiator which is cooled by (forced) air but when standing still there is no airflow so the fan starts when it gets hot to create an airflow.
It's completely normal, my old VFR VTEC started the fan at 105 C but in summer it heated up so fast it often went up to 110 C but the warning light didn't came up before 125 C.

[Alain2]

With an oil temperature sensor you can start hitting it safely at around 65c.

 

 

 

 

[Hibobb]

Life was simpler when we had air cooled bikes...

 

Now don't everyone go geeky technol on me with how great liquid cooled is.

I got some old air cooled dual sport bikes that will still be running 100 years from now.

[Canzvt]

I don't believe you have a problem. The bike did/is doing what it is supposed to do. If you have just come in from a ride and your bike is at proper operating temp (78-80C as you said), then you stop riding but keep the engine running, the engine is already warm, meaning the added heat of idle has to go somewhere (unlike warming all of the engine parts in a cold start-up). It goes into the coolant, then the rad, looking for airflow to remove the heat. Since you aren't moving, the whole engine/coolant/rad slowly heats up until the fan kicks in removing heat from the rad, and cooling the coolant, and thus engine. Totally normal operation.

 

As for air cooled bikes, HP is limited by the amount the engine can shed heat. In this case, the oil is used as a thermal transfer media removing heat from the head area and transferring it to the rest of the engine. Hopefully you have an oil cooler where the engine oil passes through an oil 'radiator' to remove this excess heat. Air cooled engines typically run at much higher operating temps than liquid cooled ones, hence are much harder on the engine oil. You will NEVER get an air cooled engine to make the equivalent amount of HP to a liquid cooled engine for SUSTAINED use. You simply can't remove the heat generated by combustion fast enough.

 

I once worked developing a Ducati 900SS engine for BEARS racing. We could only get about 105hp out of it, no matter how we tuned it with ignition, cams, exhaust etc. It was heat soaking. We increased the oil pump volume 50%, and added a larger oil cooler, and gained 15hp. Engine temps dropped 20 degrees C.

[PTrouw]

20 hours ago, Canzvt said:

I don't believe you have a problem. The bike did/is doing what it is supposed to do. If you have just come in from a ride and your bike is at proper operating temp (78-80C as you said), then you stop riding but keep the engine running, the engine is already warm, meaning the added heat of idle has to go somewhere (unlike warming all of the engine parts in a cold start-up). It goes into the coolant, then the rad, looking for airflow to remove the heat. Since you aren't moving, the whole engine/coolant/rad slowly heats up until the fan kicks in removing heat from the rad, and cooling the coolant, and thus engine. Totally normal operation.

 

As for air cooled bikes, HP is limited by the amount the engine can shed heat. In this case, the oil is used as a thermal transfer media removing heat from the head area and transferring it to the rest of the engine. Hopefully you have an oil cooler where the engine oil passes through an oil 'radiator' to remove this excess heat. Air cooled engines typically run at much higher operating temps than liquid cooled ones, hence are much harder on the engine oil. You will NEVER get an air cooled engine to make the equivalent amount of HP to a liquid cooled engine for SUSTAINED use. You simply can't remove the heat generated by combustion fast enough.

 

I once worked developing a Ducati 900SS engine for BEARS racing. We could only get about 105hp out of it, no matter how we tuned it with ignition, cams, exhaust etc. It was heat soaking. We increased the oil pump volume 50%, and added a larger oil cooler, and gained 15hp. Engine temps dropped 20 degrees C.

 

Hi,  yes I understand your explanation, I do know that if you have the bike idle after a  ride, the temperature will rise. But mine is doing it far too quick now. After parking and leaving it idle, within 2 minutes the temperature rises from 78 to 102 degrees. So therefore I am thinking of a malfunction somewhere. Especially this whole thing started after cleaning the bike, btw not with high pressure   

[Hibobb]

Yup, you are right. Better take it in to the dealer.

Please report back your findings.

[Samm]

I was out for a rip this evening so I did a quick test. outside air temp was at 19C and while riding engine temp was at 80C. Stopped and let the bike idle while watching the dash clock. In 2 minutes the temp rose to 101C. Very close to what you're seeing and only a slightly higher ambient temp. I think you're fine...

[witgen]

23 hours ago, PTrouw said:

 

Hi,  yes I understand your explanation, I do know that if you have the bike idle after a  ride, the temperature will rise. But mine is doing it far too quick now. After parking and leaving it idle, within 2 minutes the temperature rises from 78 to 102 degrees. So therefore I am thinking of a malfunction somewhere. Especially this whole thing started after cleaning the bike, btw not with high pressure   

~20 degrees in 2 minutes. Sounds about right to me as stated in previous answers, but let's just check what physics think. 

Energy required to warm up 2 liters of water from 80 to 100 is about 170kJ.
E = c dt m -> 4.2 kJ/kg * 20 * 2 kg  ->  ~170 kJ

 

Energy required to warm up oil from 80 to 95 is about (assuming 1l of oil is about 0.9kg)

2.4kJ/kg * 15 * 0.9 * 2.6 -> ~85 kJ

 

Total heat transferred to liquids alone is ~255kJ

 

One liter on gas has about 35 Mj of energy.
In two minutes about 1167 kJ is generated as heat ( 1l per hour consumption on idle, if I remember correctly this might be off). 
Roughly 30% of heat is dissipated from engine with coolant

 

35 000 / 60 * 2 * 0.3->  ~350kJ

 

So were in the right ball park. What my calculations don't include is heat transferred to engine parts and frame. Some heat is also radiated away and even the slightest gust of wind will help radiator efficiency and also cools down metal parts. Also my estimates are quite rough, but in the ballpark. 

 

So I'd say 2 minutes is just fine and there is nothing wrong with your cooling. Gas just has s**t load of energy and combustion engine mostly creates heat ....Or I've made some crude rudimentary errors with my calculations which will be pointed out in responses below 

 

 

[PTrouw]

1 hour ago, witgen said:

~20 degrees in 2 minutes. Sounds about right to me as stated in previous answers, but let's just check what physics think. 

Energy required to warm up 2 liters of water from 80 to 100 is about 170kJ.
E = c dt m -> 4.2 kJ/kg * 20 * 2 kg  ->  ~170 kJ

 

Energy required to warm up oil from 80 to 95 is about (assuming 1l of oil is about 0.9kg)

2.4kJ/kg * 15 * 0.9 * 2.6 -> ~85 kJ

 

Total heat transferred to liquids alone is ~255kJ

 

One liter on gas has about 35 Mj of energy.
In two minutes about 1167 kJ is generated as heat ( 1l per hour consumption on idle, if I remember correctly this might be off). 
Roughly 30% of heat is dissipated from engine with coolant

 

35 000 / 60 * 2 * 0.3->  ~350kJ

 

So were in the right ball park. What my calculations don't include is heat transferred to engine parts and frame. Some heat is also radiated away and even the slightest gust of wind will help radiator efficiency and also cools down metal parts. Also my estimates are quite rough, but in the ballpark. 

 

So I'd say 2 minutes is just fine and there is nothing wrong with your cooling. Gas just has s**t load of energy and combustion engine mostly creates heat ....Or I've made some crude rudimentary errors with my calculations which will be pointed out in responses below 

 

 

Thx, amazing calculations!

[PTrouw]

9 hours ago, Samm said:

I was out for a rip this evening so I did a quick test. outside air temp was at 19C and while riding engine temp was at 80C. Stopped and let the bike idle while watching the dash clock. In 2 minutes the temp rose to 101C. Very close to what you're seeing and only a slightly higher ambient temp. I think you're fine...

Thx for trying. So I suppose I never closely looked at the temperature indicator during idle.

[Canzvt]

2 hours ago, witgen said:

~20 degrees in 2 minutes. Sounds about right to me as stated in previous answers, but let's just check what physics think. 

Energy required to warm up 2 liters of water from 80 to 100 is about 170kJ.
E = c dt m -> 4.2 kJ/kg * 20 * 2 kg  ->  ~170 kJ

 

Energy required to warm up oil from 80 to 95 is about (assuming 1l of oil is about 0.9kg)

2.4kJ/kg * 15 * 0.9 * 2.6 -> ~85 kJ

 

Total heat transferred to liquids alone is ~255kJ

 

One liter on gas has about 35 Mj of energy.
In two minutes about 1167 kJ is generated as heat ( 1l per hour consumption on idle, if I remember correctly this might be off). 
Roughly 30% of heat is dissipated from engine with coolant

 

35 000 / 60 * 2 * 0.3->  ~350kJ

 

So were in the right ball park. What my calculations don't include is heat transferred to engine parts and frame. Some heat is also radiated away and even the slightest gust of wind will help radiator efficiency and also cools down metal parts. Also my estimates are quite rough, but in the ballpark. 

 

So I'd say 2 minutes is just fine and there is nothing wrong with your cooling. Gas just has s**t load of energy and combustion engine mostly creates heat ....Or I've made some crude rudimentary errors with my calculations which will be pointed out in responses below 

 

 

Nicely done. On the money. I replicated PTrouw's symptoms last night after my ride home, and the fan was running after 45 seconds (2WDW Tuned), temp had risen to 93C from 80C running temp. 20C ambient.

[motonap]

So this brings about a couple of questions

1) how hot is hot on the T7?

As what would the temp reading need to be for the warning light (if it has one) to turn on / time to turn the bike off and let it cool itself down.

 

Was out riding gravel over the weekend and the campsite we setup at was in a valley and as result limited breeze, so had temps of 100 to 107 C in no time and then the radiator fan turns on to cool it all off.

 

2) This is something that I used to do with my turbo diesel car and KTM Duke, if the radiator fan was running when I reached my destination and needed to turn it off, I would let the engine run until the fan turned off and then cut ignition. You reckon it is a good idea to continue doing that, so since the vehicle is going to stand around for a couple of hours, it will cool off either way, so shouldn't matter if the fan cooled it down to the below 100's before switching it off? 

[Ray Ride4life]

25 minutes ago, motonap said:

s what would the temp reading need to be for the warning light

@120 C the warning light goes on. Had a hose came loose not long ago and that's how i know.
After that i kept the display to watertemp a day or 2 (normally i want to see the km's) and it was going between 76 and 80 C.