These engines do get pretty hot. I remember reading that a sign of overheating is when the engine starts to cut out on power during operation. Not sure exactly how it feels, because I haven't experienced a loss of power or overheating myself, but I'm sure someone will pitch in on that in a few.
With my bike, it ran hotter than usual after going to the leanest notch on my carb needle, though that's normal. What I didn't like was that I couldn't even touch any part of the engine else I'd burn myself. When I changed my oil to Opti-2 and ran it at 100:1, the engine ran cool enough where if my leg brushed against the mag cover or gear cover, I wouldn't burn myself. It runs cool enough where I can keep a hand to the mag or gear cover during or after use and not burn myself.
Why this with a leaner fuel to oil ratio, when oil is suppose to make it run cooler, I don't know...