CX500 temp guage over-reads.

[blurredman]

Worked fine for a long time, but then a couple of months ago it started to over-read when the engine itself was perfectly fine and has sufficient cooling/anti-freeze.



It's an annoying niggle that I can't stop thinking about when I'm on a ride, let alone that it might one day prove a useful device for when the engine is actually overheating..

On every outing it usually hits beyond red. Which is completely false otherwise it simply wouldn't be working. The needle continues to gradually get higher as the engine gets warmer however, it continues past the point of normal running temperature and goes steadily towards the red and stays there until I turn off the engine.


Any information on why it might be over-reading and how to resolve please?



Pre-mature thanks.
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S, 1979 MZ TS150.
Current: 1973 MZ ES250/2 - 18k, 1979 Suzuki TS185ER - 10k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 40k, 1989 MZ ETZ251 - 51k.

[Vincent]

It could be the gauge at fault or the sender - my money's on the gauge.
'You're sure it's not overheating? Most bikes will still run hot, (for a certain time), but will be destroying certain parts, esp piston rings, bore and valve train.
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Space Is Deep

[blurredman]

I did hear somewhere that certain wires from the thermostat can give off incorrect ampage when degraded over time, and can give thus a high reading.


No, I've been using it for months now with this issue, it feels just as it did before the problem, and gives absolutely no problems and no signs of actually running too hot.


I did think that perhaps there might be a air gap in the system, and ran it for a time without the radiator cap off for a couple of minutes to see if it would clear. But it didn't.


I haven't got down to doing any real getting down and trying to resolve the problem yet. I will do so soon. I'll do some diagnostics soon then.
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S, 1979 MZ TS150.
Current: 1973 MZ ES250/2 - 18k, 1979 Suzuki TS185ER - 10k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 40k, 1989 MZ ETZ251 - 51k.

[blurredman]

Checked 7v regulator to temp guage and it read anything from 8v to 11v.

Had a spare one around the garage luckily, and i say luckily because Honda don't make them any more and as such there near on impossible to find 2nd hand let alone new. Other than building my own which I was going to do until I found a spare.


Spare read 7.08v steady which is good enough.


Have yet to test it however on a ride.
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S, 1979 MZ TS150.
Current: 1973 MZ ES250/2 - 18k, 1979 Suzuki TS185ER - 10k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 40k, 1989 MZ ETZ251 - 51k.