Reaper, you open each of your posts with how embarassing it was to go to the track.
If you are worried about being embarrassed, stay home.
Go out and have fun and worry about one person, you.
If you want to know what a 290lb person could run on a no-bar hayabusa, I'd say 7.60's are possible, probably lower. Not saying it is going to happen, or that you are going to build an all out 75" flat slick turbo bike, but it could certainly be done.
Now for a practical response...
Fill it up with plain old 87 octane pump gas.
Turn both the upper and lower damping adjustment screws on your stock shock all the way in. It still won't really be enough damping, but it is a start.
You probably need to add preload to the spring as well. Have someone measure a point from the rear of the tail to the grouns with you straddling the bike, and then with you sitting on the bike with your weight to see how much it moves. You may be nearing the end of travel with just your weight on it, although it may still have head-room since it is a stock length arm. If it is moving more than about 1.5", try tightening upo teh preload on the rear spring. Still probably won't be enough, but again, it is a start.
Make sure you are geting the bike to wide open throttle as soon as possible and hold it there. It is often easier to rotate your hand/wrist forward and get a "bigger" grip on the throttle to do this. You can lift your right elbow up to shoulder height and grip teh throttle, then drop your elbow and tuck it in while twisting the throttle at the hit to ensure it is getting open and staying there.
How are you shifting the bike (technique)?
Are you spinning or lifting the front at all? If so, lower the bike and change out to a more agressive rear tire, or tweak the tire you have a bit.
What tire on the rear and pressure?
Easiest thing you can do is change the gearing. Try a 16 tooth on the front for starters with the stock 40 on the rear, should set you back less than $30 if you put it on yourself. If you want to buy a new chain, I'd try 16/45 or 17/48 or so at your weight.
John