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74-76 GT750 temp gauge differences

Posted: Fri Jun 26, 2009 4:37 pm
by Suzsmokeyallan
On the left, a blue faced temp gauge with a PLASTIC inner face and raised markings, it has 'made in Japan ND' in raised writing at the lower section also, but its in blue.
In the middle, a blue faced temp gauge with an aluminum face and traditional printed markings
On the right, a blue faced temp gauge with an aluminum face with printed markings but no blue mark on the left and the centre mark has been shifted on the face.
The one on the right is the only one ive seen like this, a bit different in the way the face has been altered.
I believe the little dots on the face between the middle mark to be voltage test resistance settings for adjusting the gauge in the factory.
On the plastic faced one these are little raised dimples but are not painted white, they are the same colour as the face.

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Re: 74-76 GT750 temp gauge differences

Posted: Fri Jun 26, 2009 8:16 pm
by pjmcburney
Suzsmokeyallan wrote: I believe the little dots on the face between the middle mark to be voltage test resistance settings for adjusting the gauge in the factory.
On the plastic faced one these are little raised dimples but are not painted white, they are the same colour as the face.

Allan,


Nice research, who knew there were so many differences?

That's a reasonable assumption about those marks, but it seems coincidental that those marks (raised or painted) happen to also adequately describe the lower and upper normal operating temperature range...

Well at least they do on my bike.


Cheers
Paul

Posted: Sat Jun 27, 2009 8:06 am
by Suzsmokeyallan
Paul you never know whats going to show up on these gauges. Theres all sorts of little things different in them you cant see because they are hidden in the gauge. Besides face alterations things changed such as internal mechanisms design, or certain parts made of metal that were switched to plastic and so on.
In these temp gauges theres actually three reference adjustments, one moves the whole mechanism for adjusting the needles rest point and the other controls the bimetallic strips deflection position. Then theres also a cut off contact point that allows the mechanism to 'cycle'
Therefore id deduce they apply a reference input and the needle should deflect to the lower mark, then they apply another reference input and it should deflect to the higher one. Then it will cycle at that higher mark with the reference input due to the contact points adjustment and the other bimetallic trip its attached too.
Its all a 'general reading' thing here cause the gauge isnt accurate to the degree of a true thermometer but its got to work to be accurate to some degree.