'Bout 40 years ago I worked with a fellow who (in his younger days) was best friends with Dan Blocker. That led to a chance lunchtime visit with an older Hollywood stuntman. He explained that they could make "real nice wobbles" by loosening the front axle nut and the front fender bolts. It allowed lower speed for the wobble, and safer get offs for the crash scenes. It helped to run the right speed on a surface that had some evenly spaced bumps or grooves to get it working for you.
None of us knew anything about "gyroscopic precession" in those days, I bet. Now you can learn all about it on the internet. You only have to be able to tilt that spinning wheel a tiny bit, and it will turn itself into each tilt for you.
So....now we all take off the braced front fenders and go real fast. Add some extra rake, along with too soft front springs and no travel limit....hmmmm.
JimL
PS: for the last 3 years, I've been running schedule 40 PVC or ABS (slotted and hose clamped) on my forks. With travel limited to about 1/2" under power (and zero on decel) the front end stays planted. I actually learned this by accident, when I was curing too much front end lift by closing down the fairing opening above the front fender and adding forward weight. I was trying to protect my paint on the top of the front fender, and the bike suddenly became more stable. The older I get, the slower I learn.
You can see it in this pic, on right edge....shown with no front wheel at full extension.
http://www.landracing.com/forum/index.php?action=dlattach;topic=12670.0;attach=40505;imageIf you do this, be sure to pull them off and clean/oil the tube during cleanup. I cut about a 3/4" wide slice out of the ABS or PVC so they will snap in place to hose clamp....no need to disassemble the forks to install or adjust.