Actually, Danber's suggestion is going in a good direction. The Sig CCW jacket is a great concept.
If you know a good seamstress, having a pocket of sturdy material stitched into the inside of your riding jacket would be a good idea.
8shot - It would much easier, faster, and safer (legally and physically) to just rip the throttle and get out of the way.
I say legally because to claim self defense in Ohio, you have to prove you had no way to get out of harms way. If you had time to unholster your weapon and discharge it, you would presumably have enough time (OP said he rides a GSXR and even though its weeee little 600
it can still go zero to 60 in 3 seconds)
In MY typical riding gear (ICON jacket, ACU's and desert boots) it would take about 3 seconds to unholster and fire while riding. (Timed it, and it was an average of 2.7)
Riding jackets are tight and awkward to draw from a holster with. Unzipping and pulling out from an interior pocket would be much faster (assuming your jacket can unzip smoothly.