Cooling

[cbrdude]

Hi guys,
I have a '92 NC30 import. This has always run hot. Over the winter I put a set of new radiators & hoses on. Ran clean water through it & then refilled the system with pre mixed water / coolant.
Took it for a spin yesterday & the needle is around 90 while travelling. In slow / stood traffic the needle rapidly rises to the H. The fan comes on & it drops slightly. I'm sure it shouldn't read that high.
Any suggestions or ideas would be most welcome.
Cheers. Pete.

[manicguitarist]

Does the fan come on?
Once you get moving again does the temperature drop to normal?

If so - this is *exactly* what my NC35 does. Don't worry about it. They get hot very quickly when not moving.

[cbrdude]

Hi manicguitarist.
Yes the fan comes on but it only drops slightly. Yesterday it wasn't a summer scorcher but the needle went past the H. When the fan kicked in it dropped to 'beginning' of the H. Once I was moving it dropped to 90 ish after a couple hundred yards.
Cheers. Pete.

[Neosophist]

shouldnt go past the H unless you were on a track or something and suddenly stopped and got a quick spike.. quite rare.

I assume the system is bled properly.

New rads or second hand? Any cold spots in them?

Have you had a look at your water pump? Many of them have been neglected with bad coolant and impellors rusted off.

How is the rad cap?

Thermostat ok?

[magg]

Inaccurate temperature sensor/gauge perhaps. Is engine running as hot as gauge suggests?

[manicguitarist]

Inaccurate temperature sensor/gauge perhaps. Is engine running as hot as gauge suggests?

Yeah, I was wondering that.

[cbrdude]

Hi guys,
New clean 2nd hand (after market [?]) radiators. Cores / fins in great undamaged condition. I bled the system up to around the 90 degree mark, by which time the coolant was bubbling & spitting out of the filler neck. Replaced the rad cap at this point. Expansion tank to just below max level.
Doesn't appear to have any coolant loss on the road or drive. The frame gets hot but always has. (had the bike 10yrs)
I might put my original fan sender switch back in the rad instead of the supplied one. Guage didn't go beyond H before with clogged rads, only up to the H. :/
Cheers dudes.

[cbrdude]

Hi guys,
New clean 2nd hand (after market [?]) radiators. Cores / fins in great undamaged condition. I bled the system up to around the 90 degree mark, by which time the coolant was bubbling & spitting out of the filler neck. Replaced the rad cap at this point. Expansion tank to just below max level.
Doesn't appear to have any coolant loss on the road or drive. The frame gets hot but always has. (had the bike 10yrs)
I might put my original fan sender switch back in the rad instead of the supplied one. Guage didn't go beyond H before with clogged rads, only up to the H. :/
Cheers dudes.

[magg]

Fan is separate switch, yours appears to cut in at H mark, odd as should operate at approximately 90 degrees. So fan switch thinks H is 90 degrees or temp gauge thinks 90 degrees is H. Someone must be wrong. Histoy suggest temp gauge sensor is suspect, getting less accurate with time.

Normal running 70-80 degrees, stopped in traffic rises to 90 degrees then fan cuts in and temp oscillates around 90 degrees as fan cycles on and off until bike moving again and temp falls until bike stops or slows again. Cycle repeats until engine is stopped.

Suggest you check temp sensor, temp gauge and fan switch.

[cbrdude]

Cheers magg.
Job for another day. Think I'll stick to riding my 'Blade. No dramas with that one.