Temp Gauge Calibration

[wolfy]

I've been worried about my engine running hot, however it doesn't behave like it is, yet I notice my temp gauge goes very high - however it jumps to half-way up immediately on turning the ignition on, so I'd say I have a zero-calibration problem. I'm at a loss as to how to adjust the instruments for this - anyone got any pointers on this? Can't find anything in the Haynes Manual or by googling. Apologies in advance if it's staring me in the face...

[hairyuk]

wolfy
i would try another sender unit
i think its in the radiator lh side
it gives a signal to the gauge in the spedo
i would say the chances of the guage being wrong are low
and the temp sender higher
if you are any where near leicester we can swap it and see
mark

[wolfy]

Thanks mark - I took a gamble and picked up a radiator sender (which I think is for the fan/thermostat circuit) and an engine sender (which I think is for the temp gauge) from ebay, so I can swap these and see. The only radiator sender I could find is for a BROS 400 but it was only a few quid so I'll gamble it's a similar part. By the sounds of your diagnosis it's the engine sender so I shall probably replace it and see what happens - I don't know what effect age and decay would have on a sender but I would imagine it would tend to a short rather than to an open circuit.

[wolfy]

Also the fan has only cut in once since I've had it and there's been some pretty hot weather, so I picked up a cheap thermostat in case that area needs looking at. Eventually it probably will, anything with water in it is subject to the ravages of time, Honda or no Honda

[De Graaf van Salland]

I've had my bike for years and the fan has only worked once or twice (read my Beaulieu-story: www.ntvhonda.proboards.com/index.cgi?board=logwayround&action=display&thread=2291&page=1; go to day 2).

When my thermostat was broken, my bike ran too cool.
I took photo's etc. but I've yet to make the web-page to my site about replacing the thermostat.
So this is all I've got about the cooling system:
www.stoeretassen.nl/My_NTV650/Koeling/cooling.htm

GvS

[wolfy]

That's great stuff, thank you! In view of this info I'll replace the gauge sender and if that works for the gauge and all else still runs and behaves fine, I shall leave well alone and simply enjoy having a few spare parts in the garage. You never know when you'll need them.

[smartiedarkblue]

hi all,

The sender in the side of the radiator that you speak of is purely for the fan, it has nothing to do with the temp guage.

The one for the temp guage is a whole lot more fun to get to, it is plugged into a sender that is attached to the underside of the thermostat housing.

if memory serves me right, then drain the coolant, remove tank, remove airbox, unclip cooling pipes, unbolt thermostat housing, the sucker is in there.

ed

[smartiedarkblue]

Also if your fan is not working then check the earth on the back of the radiator.

I have posted this before it is a achilles heal of the ntv, the earth wire and the fan mountings are exposed to all our luvley brittish weather and salt and corrode easily.

if you prove this and it still doesn't work, if you put 12v straight to fan + / - . using a piece of spare wire from the battery this should spin it over.

If not then the brushes in the motor are sticking, its not a hard fix, just remove the fan and undo the back plate screws of the motor, then seperate and inside you will see the carbon brushes give them a prod and they should move free and easy back and forth. if not then spray spareingly with wd40 and work them gently. it will soon work..........

ed

[wolfy]

I've had a look for the gauge sender - at a pinch, I reckon I can swap it out without having to remove the whole thermostat housing. I'll let you know how I get on though

[wolfy]

Well, I swapped the sender and the gauge still goes up to half way when I turn the ignition on, with a stone cold engine, and in full riding use gets up to the top, which would suggest half way like most people's reports on running temperature that I've managed to search out. So, it looks like the gauge itself is a bit out. There's no means of adjusting it (that I can see), so as I need to replace the casing of the instrument cluster (it's cracked and I've had to apply gaffer to hold it together), I will probably just carry on keeping a lookout for a complete instrument cluster on ebay.

In the meantime, the engine is performing fine, so I've just ordered one of those Moto-Detail oil gauges which replaces the dipstick. I'll report back on that when it arrives.