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2021 CB1000R; 2018 CBR1000RR SP
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Discussion Starter · #1 ·
Our ambient temperature is hovering around 40's - 50's at this time of the year and the typical engine operating temperature of my CB is around 180 degrees Fahrenheit (or 82.22 degree Celsius).

What is yours like?
 

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Riding around general 30 - 40mph roads with occasional stops at traffic lights - seems to hover around 80 - 85 degrees C.

Motorway at a steady ish 70mph stays around 76 - 80 C.

In town crossing London (30 mins of 10mph, with very frequent stops) can hit 103 degrees C
 

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Discussion Starter · #4 ·
The reason why I am asking is that all of my 4 cylinders Honda's hover around 180 degrees F (82 deg C) on easy going country roads (below 55 MPH), without a lot of stops and my Kawasaki Ninja 1000SX has an operating temp at around 140 degrees F (or 60 degrees C).

Not sure why Honda favors a higher operating temp vs Kawasaki's cooler engine.
 

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Discussion Starter · #6 ·
Warmer is actually more efficient, if I remember my schoolboy physics correctly.
That's the part I don't quite understand.
I thought cold air entering into the combustion chamber is denser and will give us a bigger pop.
 

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this is for cars, but the principles ought to be the same. highest power from normal operating temps, but with intake elements cooled, to keep the air charge dense. not that this is the situation with normal motorcycle operation, of course... but perhaps of random interest...

 

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Modern cars typically aim to stay at 90 degrees C for best operating efficiency - so the CB1000R seems to be right around that mark most of the time (if a touch over in slow traffic).

I don't worry about it.

In most cars, the temp display is deliberately 'damped' so minor variations in temps whilst stopped at traffic lights don't show as massive spikes on the guage. The bike just moves straight away, which can be disconcerting.
 

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...
I thought cold air entering into the combustion chamber is denser and will give us a bigger pop.
Not that simple.

Even the name of the scientific approach is hard: Stoichiometry.
Gases keep a close physical relation between pressure, volume and temperature!

Run a piston engine airplane and figure out that temperature gradient up won't always give a "bigger pop".

On the CB1000R, no racehorse by far,
with her ginormous barn door sized air cooler and her fancy drum magazine oil cooler
the engine coolant temp is well managed.

Powerful cycle have a temp sender that shows the temp on the dash for the driver.
And another temp sensor, bolted on the cylinderhead for instance,
info for the engine management computer.
They give different readings.

The dash temp from ECT sensor on the CB1000R is no aerospace specs precision instrument.
80°C ~ 85°C would be normal operating temp.

Stopgap DIY to keep engine temp at acceptable level:
Tire Wheel Vehicle Automotive tire Motor vehicle
 
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