Motorcycle Repair: Carb, cb series, 750 honda

Question
is there a danger in leting a bike run for a long time while trying to tune the carbs, being a rookie, i watched as a one of my instrctors let the bike run for some time which i thougt was kind of against what i was taught, i even seen oil starting to leak from the engine, finally he let the engine cool, but didn't use a fan as was the instructions, were talking some 20 minutes, and no the lessons was not about what will happen if you let a bike run for so long without a fan, it was a 1978 cb 750 honda.

Answer
Hi Charles.

Yes, there is a danger in that.  Every reputable mechanic has a fan blowing toward the engine when running it.  Particularly on air-cooled machines, like older CB series, et al.
 You should even do it with liquid-cooled machines, although it is not quite as critical it is better.

Good luck with your courses and ride safe.
FALCON