Re: How to tune an engine with a temp gauge?
Too lean will cause the motor to over heat, this is what will damage the engine.
Too lean can also give slight power increase, so can be that you might think your motor is running better, but it's lean and getting hot.
My C to F conversion isn't very good, but I find if my motor runs up around the 150 C or more it will start staining the underside of the piston, and in my opinion is starting to get to hot, I've heard of people getting their motor hotter, I've been told 180 C is OK.
As you probably know extra fuel helps to cool the motor.
I like to ride my bikes fairly hard and live in the tropics, So I generally like my motors to 4 stroke unless I'm on the throttle, which tends to give best acceleration as the motor wants more fuel under load. That's generally how I tune mine, by ear, but I have been around engines all my life and can hear when one is running right, then check the plug. A better pipe tends to make tuning by ear a lot easier.
The only time I have had over heating problems is when running higher compression with an angle fire head. The Puch head is the go if your going to try and make some real power.
My case induced motor with the Puch head does over 50MPH and runs cooler than my milder motors with less compression and a straight fire.
Any one after performance, throw away your angle fire heads!