Strictly referring to the CBR250 (that is, a 250cc sport bike), if we wanted to get really technical about it, one could assert the fact that "rock climbing, hand gliding, scuba diving" are not hobbies whilst a motorcycle differs in that it is in fact a hobby:Hobbies are generally the free time pursuits that are not, a, athletic or b, dangerous.. You can be very very serious about stamps and coins, or refinishing old furniture. Amateur astronomers have discovered many new and objects in space because of their seriousness and dedication.
But if you are a crappy astronomer, undedicated, and incompetent there's no danger to yourself.
Rock climbing, hang gliding, scuba diving, motorcycling are not hobbies.
hob-by (n.) - a small horse or pony
But in the more common use of the word (an activity done regularly in one's leisure time for pleasure), I do find motorcycling, and the risks it involves, to be an activity requiring as much of one's attention as possible, that is, in the area of continual practice and improvement, as in a career skill or perhaps more emphatically, life skill, and not something that should be done "when I get around to it" or "if I have free time." It is a very serious activity but I'm sure most of us already realize that by now
On a side note, I just finished and pass my MSF course this past weekend, and I even got to train both days, practice, and complete the skills test on a Honda CBR250 Got a bike lined up for this upcoming weekend, pending inspection passing and will be looking into taking the Experienced Riders Course not too long after.
"One does not simply master the motorcycle."