normally engine should be run below 130 degree celcius or 266 Fahrenheit.
when u tune down your hsn from 2 1/2 to 1 3/4 turns, definitely temp will rise. that's the fact
the next time u don't have to follow exactly what people wrote in forums. maybe its true on his side of the story due to his location ambient temperature, atmospheric pressure and humidity or maybe engine status.
every time i change my pipe, i would richen out hsn needle by at least 1/8 turn. then i tune to temperature. sometimes by sound,acceleration or even smoke as indication.

since u over heat ur engine too much, its better u check with LHS or any one with engine experience regarding ur engine condition.

hope this help