Motorcycle Forum / General / Technical / October 2007

How hot, and what temperature would you like it to run at?

I'd recommend you leave it alone.

One time I had a T-Bird (Ford, that is) that kept boiling out all its coolant
and I kept replacing the coolant. I tried removing the thermostat and
rebuilding the water pump, but it didn't help. Turned out that the radiator
was all plugged up.

Modern engines usually have a thermostat which makes them run hotter than
older car engines. And they run high pressure radiator caps to raise the
boiling point of the coolant.

Hinkley sent their engineers to Japan to study how Kawasaki built motorcycles
and some Kawasakis (like the original 900cc Ninja) ran so hot (around 275
degrees F) they scared riders and Kawasaki recalibrated the temperature gauge
with a 1 ohm resistor so the gauge wouldn't go into the red zone.

Before I would remove a thermostat from my motorcycle, I would research what
the normal running temperature was supposed to be, what temperature turned
the fan off and on, what pressure the radiator cap was supposed to be and
what temperature the thermostat was supposed to open at.

Then I would attach a cooking thermometer to the coolant hose and see how hot
the hose was getting.

I would check everything before removing the thermostat.

One time I had a Suzuki Water Buffalo that wasn't pumping water. Turned out
that the water pump was full of a fibrous leak sealing material, so it
couldn't pump.

I had an '01 Thunderbird and the temperature warning light would often come
on if stopped in traffic on a hot day. About the same time the fan would
come on, cool things down, and then the light would go out. I did some
research and found that this was normal behavior for this bike. The warning
light and fan, while triggered by separate sensors, were both designed to
come on at the same temperature. If this is what you're experiencing, I
wouldn't worry about it.

Martin