Temp gauge straight to HOT

[V4beermonster]

Hey up guys,gals right have just fitted the radiators to my project bike, and filled with coolant as soon as I started the bike the temp went straight to Hot! Have tested the gauge by earthing the sender wire goes to Hot, so Haynes manual says sender faulty swapped with known good from my other bike and it does the same! Any ideas

[Delboy]

Could be the gauge? I know it's a pain, can you try the gauge from your good bike?

[V4beermonster]

Guage seems ok doing what ment to, miffed with this one mate

[johnnie5]

its one of

the sender
the gauge
wiring

or its actually getting too hot

have you run the bike with cap off till the thermostat opens and gotten all the air out ??

[Neosophist]

You'll ruin the gague if you keep it at hot for so long (as it says in the Honda manual)

Your problem is that there is no earth.

If you disconnect the earth then the gauge will go straight to hot. You have either disturbed or broken the earth wire to the gauge. Easy enough to follow from the gauge.

[V4beermonster]

I have had all the clocks apart to powder coat the brackets will get in the shed in bit test some of the earths. It's not running Hot gauge goes straight to hot even when bike is stone cold

[speedy231278]

Is the bracket part of the electrical circuit between the battery, sender and gauge? Is it possible the powdercoat is interrupting it?

[pip]

A short on the wire that goes to the sender.

Phil

[V4beermonster]

Right sorted 12v to gauge ok, earth ok and continuity between sender wire and gauge!!! All checks out so changed gauge and is working fine now so Faulty gauge it was then. Cheers for the input lads and Delboy you were right. Phil

[Neosophist]

Ah, I didnt realise you didn't know the condition of the gauge (I just assumed it worked before you fitted the radiators)

Tip for the future.

Most common fault for one that was working and suddenly stops is either no earth or missing sensor wire. If you pull either off the gauge will go straight to hot as soon as you turn the igntion on.

According to the Honda common manual this is a valid test for the gauge movement. However, if the gauge is left in the "hot" position for more than a few seconds they say it can permanantly damage the gauge...

Either way, glad you've fixed it :)