I ran one on my C90 with a larger engine fitted. They're pretty unreliable tbh, mine leaked oil too. After a while the temperature gauge got stuck as I assume the metal strip had warped.
There's a small electronic one you can get for around £30 that uses a washer round the spark plug that's better... I'll find a link..
Sensor is too long for the TTR and fouls on the gearbox internals. I tried it without the gauge to see if it was any good just as a replacement plug but the thread is too coarse. Fortunately it was only £3.22 wasted!