The KLX 650 shown in my profile was nicknamed the "Bone Breaker" because it did! That bike was the wildest dirt ride ever! It was a single cylinder 4 stroke, 4 valves, water cooled, dual overhead cam with 50 horsepower. I broke my right hand and several ribs aboard that bike! Tweaking the throttle on that 650 got the front wheel to stand at 12 o'clock instantly.
I also had its smaller brother, the KLX300 that I rode for a week in the desert at Belen New Mexico.