Fuel and Temperature Gauge

the new speedometer gauge I'm using have the option to connect fuel and temperature gauge
when I connect the water temperature gauge it is going to the red quick after the bike is on for few min
the water temperature thermostat is new
the fuel gauge is not working at all, I am not sure if the issue is the fuel gauge or the speedometer
anyone have an idea how to adopt the original water temperature thermostat to work with the new gauge, I'm thinking I need to add a resistor ??
for the fuel gauge, how I can test it first to make sure its working
I am also thinking to add external temperature and fuel gauge if they will not work as part of the speedometer, any suggestion ?

Thank You
Eran

Eran,
You started a new post instead of continuing on with a build post on your project, so it doesn't help.
If I remember right you're installing a M unit on the bike?? and trying to marry in the existing sending units?? Can you update this topic please? maybe we can help.
KB

move the post to my project post

Have you still got the original instrument voltage regulator in circuit? Just a thought.