How hot is too hot?

[37monkey]

The temp gauge on my bike has never reached the halfway mark, I've never heard the fan kick in, but the right side of crank case seems to get really hot, that and it smells hot, to the point others have commented. It runs fine, hasn't missed a beat, all the fluids are clean and within acceptable levels. Is this just how the bike is? Thanks

[Richard230]

I don't know what model F800 that you have, but my 2009 F650GS has never had its fan come on and the temperature gauge has never risen above the first mark on the gauge no longer how long it idles. However, I can't say that I have noticed the right side of the engine become so hot as to be worrisome.

[flyrider]

What kind of riding are you doing? Around urban areas or out in the wilds at constantly changing speed, with good airflow?

[chris f]

The Electrics Alternator sits behind the right hand cover. It is of a fairly basic design running at a constant output and "dumps" output in excess of what bike systems using as heat. I don't think you have a fault.

[Panuno]

My ST is the same - on the temperature gauge - when riding in the UK.
However, touring on the continent in 40 degC air temperature, and cross navigating a city....I've not only had the fan come on, but the red flashing warning triangle as well.
But once out of city traffic, and even in that heat, then temperature is back to normal

[PhotoAl]

Mine seemed to run quite hot but the temp gauge would get to the half way mark and stay. It didn't vary much more like a car than other bikes I've had. Mine did overheat once (actually a couple of times on the same day). If coolant is low enough for the cooling fan to not be able to cool it the gauge will quickly go from midpoint to an overheat condition! 2 maybe 3 minuets if my memory is good. My overheat was caused by a lack of coolant (water - thanks service folks), interestingly it would cool off rapidly even at 25 mph! Cooling system is robust, the engine is very efficient and since it runs lean for efficiency it run hot - that is different than overheating. I never had any problems with mine although it saw lots of miles at interstate speeds in 95F and above temperatures. It didn't like to run a lot over 80 when fully loaded and the temperature was 95F. It would but the fuel economy plummeted and the heat pumped off the bike was substantial. After running during hight ambient temperatures it would sometimes make a pop when re-starting. I wondered about it but had it serviced by the book and therefore didn't worry. I'm not even sure what oil they used - I'm sure it was the "low cost" BMW stuff.

EDIT: I'd ride it like you want to and don't worry.

[AutoXer-1]

As a reference point my 2016 F800GT temp gauge runs normal and the fan still comes on quite often during slower riding / stop & go stuff.

[ParallelTwinz]

As a reference point my 2016 F800GT temp gauge runs normal and the fan still comes on quite often during slower riding / stop & go stuff.

Suggest you get a Harbor Freight IR temp gauge and read the radiator temp as well as other spots on the motor. The temp sensor on an older bike can fail, preventing the fan from coming on when it needs to. Trust your instincts. If it's hot, it's hot. Sensors are cheap, motors are not.

Also, check rad flow-remove rad cap cold, crank, and watch for flow with the same gauge. May be the thermostat sticking as well. Cheap stuff to fix.

[petespace1]

I have a 2015 F800R and when riding in low traffic areas the fan does not come on.
In stop start urban traffic with plenty of intersections with signals (read stopped traffic) it comes on fairly quickly, depending on whether its a winter or summer day.
26° Celsius days and above it comes on quickly.

[Roy Barnes]

The Electrics Alternator sits behind the right hand cover. It is of a fairly basic design running at a constant output and "dumps" output in excess of what bike systems using as heat. I don't think you have a fault.

The right side cover will run at least 50 degrees F. over any other part of the engine. That is why the stator has a shorter life. Mine would last about 50,000 miles and it was time for a new one.