From "More Proficient Motorcycling":
<the author was talking with> a German motorcycle instructor who taught fast riding at the famous Nurburgring racing circuit. He went on to suggest that he could usually predict a rider's relative skill level by observing the students as they arrived for class: "Let me see a rider maneuvering around the parking lot, and I can tell you how good he is at higher speeds"
I usually do a couple of exercises:
1) weave through the lines/spots at various speeds
2) moving across a row of 10 or 20 parking spots, start and stop with the front wheel on each line (so, repeatedly start and stop in about the width of a car, or the length of a bike) without putting a foot down
3) do repeated figure 8's within 4 parking lot spots (a 2x2 rectangle), without touching the outside lines
4) straight-line hard braking. If there's a patch of sand available that's good too (I use this to work up to recovering from a locked front wheel)
5) tight circles in 2nd gear until the pegs scrape. I do this mostly to scrub in new tires
These are considerably more demanding than the M1 exit exercises, which as I recall weren't too strenuous. I'm usually pretty tired after 20 minutes of the above, since they all require very deliberate control inputs. In particular, the start/stop exercise requires firm inputs to both throttle and brake and the figure 8 exercise requires a lot of body positioning and lock-to-lock steering, rear brake control and good visual focus.
The point with any kind of practice is to find an exercise that is challenging to you, whatever your current skill level happens to be.
