yeah, ive never had it before. Im really hoping its just the tire, it was perfectly fine all day riding, then at the end of the run it started to shake when no weight was on. Yeah I adjust the chain, and as far as I can tell the axle is set straight.I have an 07 just like you. I ride the same area as well. I have never had headshake out of no where. Suggestions for heavier bar-ends or a steering stabilizer are bogus. Those are just band-aids on the problems. I would be will to put money on the front tire being shot, or the steering stem either loose or worn head stock bearings.
I have 21000 miles on my machine. I ran the first year without tuned suspension and no stabilizer. I could let go of the bars, and move forward or backward without any issues what so ever!
If you never had the problem before, then its obviously a faulty part issue.
Do you adjust your chain on your own? Is the axle alignment correct?
I am as fimiliar with the 07zx6r as you can get. If you need help, let me know. Also, hit up blackman's cycles in emmaus for great prices on sets of pirelli diablo tires. I bought the last michelin PP2ct set they had on sale. I paid 210. The pirelli tires were 180 a set.
..damn you! lol I was going to get a Set, im still going to see if they have any instock. If not ill grab the diablos, I hope theres a set for me Im calling them tomorrow to set up a date.