I ran the Saturday Sears Point AFM practice and was doing very well, especially after the CSS Level 1 I took on Monday. I had my lap times down to 2:13 (I'm on an ex500), which is the fastest I've gone at Sears. I had some serious brake dive on corner entries so I asked my suspension guy for some input and he recommended adding preload to my F3 forks. I added 8 mm at the beginning of Sunday practice and the dive was significantly reduced. I was slowly working my pace up that morning due to the cold track and cold tires and my first lap was 2:30, my second 2:19. On my third lap I lost the bike on the entrance to T7. I was going pretty fast on the dragstrip to get heat in my tires so I braked pretty hard for the turn. I was still more or less up and down - maybe I was 5 degrees leaned - when the bike just went. It felt as though I hit a patch of oil or something. The cornerworkers said there was nothing on the track there, and nobody else had the same problem. The strange part is that the bike and I both went down on our LEFT sides.
I hadn't grabbed the brakes, but was easing them on.
my tires, when the bike finally made it back to my pit, were at 23 psi front and rear, which is where they should have been according to the Bridgestone tire guy.
I can't identify any mistake I made in riding that would have contributed to the crash.
My rear tire had only the CSS day and the Saturday practice on it. The front had an additional 10 laps from a 600 supersport before I bought it.
Apparently the Bridgestone slicks take the longest to warm up an any slick, but the Bridgestone guy said 3 laps should have been fine. Also, I don't have tire warmers.
The only thing that seems to have possibly played a part is the preload. I tested the front end when the bike came back by pushing down on it and it was awfully stiff. Since the bike sustained minor damage (peg, bar, engine case, slider) I don't thing the forks are twisted or sticking so the stiffness is probably a result of the preload adjustment. Before the adjustment I had 37 mm of rider sag. The tires also looked a little funny. Cold tearing and just general raggedness - I don't really know what else to call it.
I am truly in the dark here and want to at least come away with some idea of what happened and what I can do in the future to keep it from happening again.
Does anybody have any idea?