temp gauge

[poncaprince]

i have a 78 that them tempgage reads hot, its not loosing radiator fluid and the reserve tank is full, its not steaming either, but the fan kicks on, any advise thx

[virgilmobile]

The fan switch is a separate circuit from the gauge.The fact that one reads hot and the fan kicks on,indicates that in fact,it is running hot.
with the bike cold,pull the radiator cap,top it off with fluid.Start the bike and let it warm up.
While it's warming up,some expansion will push some fluid out of the top
***What your looking for are bubbles in the fluid,as it gets warmer,more bubbles****
If you see this,a head gasket is leaking into the water jacket.
If you don't see bubbling,there may not be water flow(a broken impeller on the water pump or stuck thermostat)
Another possibility is there is air locked in the cooling system.

[poncaprince]

i looked in radiator cap no bubbling, but after about 3 minutes level in radiator rose to the top of lip, thermostat is problem? i can i tell if it needs replaced or unstuck, the bike sat for four years before i got it, changed oil an antifreeze an brake fluid, lookin into filters, thx again, first project im conqouring myself so i learn, what it runnin smooth before i take it for a long trip

[Fred Camper]

What to you mean when you say "it is running hot". When the fan normally kicks on, it is not running hot. It is running hot when it is pushing steam and cooling out into the overflow and making quite a commotion. So maybe it is just warmer than you expected, but please clarify.

[poncaprince]

the temp gauge is reading about at the 3/4 mark higher not all the way over, no steam or overflow spilling, just want to make sure thats normal thx again, been riding mostly air cooled bikes my gl500 was a differnt type engine so nothin to compare to except a car

[virgilmobile]

While tooling about town,My 1100 and 1200 will sometimes rise in temp(almost to the red),the fan kicks on and runs till it cools back down to the 3/4 mark.Note that this is in stop and go traffic.On the highway it settles about midrange and stays there.
Can i assume that this what you mean in your first post?It should not be overheating enough to turn on the fan when cruising down the road.

[scotterichmond]

There is no substitue for a digital termometer and checking the "real" temp of the coolant.
Anything else is just guessing.

[Fred Camper]

You should not feel you are overheating unless the overflow is activly spitting while running, and in this condition the needle if working should be in the red. The 3/4 mark is not approaching an overheat as this may just be the fan turn on point depending on the mechanical calibration.

[poncaprince]

ok thanks for the info, i guess i got concered over nothin, ya live an learn

[portugeezer]

Better to ask and know it's ok than to chance damaging the engine IMO