Could someone translate? I don't speak...

[K31Fan]

Please tell, what kind of bike / engine ?
However, it is not so simple. If you run the bike easy on city streets, have to be super lean mixture and some other problems if it boils.

Depending on engine and circumstances, blown head gasket does not always mean huge amount white smoke and "milk".

Its a 1995 zx7-L3. So far the motorcycle has only been overheating at idle, or slow speeds. It seems the air rushing around it at highway speeds cools it enough to keep it under correct temp...wait, wha-? How do I diagnose a head gasket leak then?

Bad Radiator Cap......... and a bad seal do to a crash from before I owned the bike the neck was messed up a bit.. smoothed that out and a new cap.. problem gone.

Sounds like a damn good idea. I'll bet my local Autozone would have one.

If its not at least a 50/50 mix, your boiling point will be too low, and youll have your problems.

The coolant came premixed 50/50. So I may be incorrectly assuming that the manufacturer mixed it correctly. But that seems a little out there to me. What else would you like to know about the bike? In terms of miles it has 13xxx on it, and it's a 1995 Kawasaki ZX7-L3 model.

What type of test did you do checking the water pump's function?

I saw the coolant get sucked back into the bike when I blipped the throttle (also makes me think it's not a head gasket problem). And I took the water pump cover off and saw the impeller turn while the engine was running. The impeller isn't loose, and it won't turn after the engine is off since it's gear-driven.

Timing. incorrect timing will cause over heating / lean running

Good idea! That's definitely a possibility. I haven't worked on the timing yet... Are you talking about ignition timing? Engine timing? Or are they both the same thing?