Well, tearing down the engine to pull the crank to have it lightened and rebalanced would be a pretty big deal.
Pulling the counterbalancer on the other hand is pretty much a free mod. The next time you have your exhaust off, just drop the pan and pull the balancer- you can do it yourself, it's not rocket surgery. Just MAKE SURE TO PLUG THE OIL HOLE IN THE SHAFT before you reinstall it. In and of itself it won't make a night-and-day difference in the performance of the bike- it's not like adding a turbo. But it's free, it makes the bike so much nicer to ride, there is a noticeable improvement in acceleration, and when you add up a number of smaller gains, it starts to become significant.
As far as keeping the liter bikes off you, That's really not going to be an issue. The Hayabusa does many things well. The liter bikes only do one thing really well- road racing. Even on a road race track, the only time a liter bike is going to have an advantage over the Hayabusa is in actual road racing (not track days), and only at the EXPERT level. Obviously, the Hayabusa should not be someone's first choice for expert-level road racing, but a well set-up nearly stock Hayabusa is about 90% as good as a liter bike.
If you decide you want to go this direction, there are some other relatively minor changes that you can make, that will make the Hayabusa significantly better.
One of those changes is tire sizes. The Hayabusa comes with a 190/50 rear tire. 190/50 tires don't provide much traction, and they make the bike steer like crap. When it's time for new tires, just replace it with a 190/55. Since you were going to have to replace tires at that point anyway, it basically costs nothing to make a huge improvement in traction and steering:
http://www.suzukihayabusa.org/forum/index.php?topic=85775.0There's also some cheap and simple upgrades that you can make to the geometry of the bike that will make it handle a lot better. A $15 pair of 1" raising links can be installed in a few minutes in your driveway. Shortening the final drive two or three teeth will shorten the wheelbase 5/8" to almost an inch, and can be done for next to nothing (by taking two links out of the chain for example). I think you can still slide the fork tubes up in the triple clamps a little bit (up to about 13mm is good), and that also costs nothing. Each of these changes makes a noticeable improvement in the handling of the bike, and the combination, (along with the 190/55 rear tire) transforms the bike:
http://www.suzukihayabusa.org/forum/index.php?topic=75439.0There are also a TON of weight that can, and should, come off your bike. The steel bar end weights weigh about a pound EACH. Remove the steel front footpeg weights, the stock crap tool kit, the tank prop rod, the snow shovel, the Frankenstein bolts (replace with shorter allen head cap screws), the grab rail, two of the four grab rail bolts (one on each side), the passenger pegs and the left peg hanger and mounting bolts (if you're not using them), the PAIR system, the exhaust system (replace with the 4-into-1 exhaust system of your choice), and on, and on, and on. IF it's legal where you live and IF you are safe to ride without them, you can also remove the rear view mirrors. You don't need expensive mirror block-offs, just use a pair of small black plastic zip-wraps to secure the upper fairing to the "ears" of the fairing stay, right through the bolt holes. Note that this is also an aerodynamic improvement, and will prevent the mirrors from breaking the fairing stay and/or the fairing if you should go down. I was able to literally unbolt and throw away an easy 50+ pounds from my bike, and it felt like it. I ultimately got my Hayabusa down to within about 25 pounds of a stock liter bike. The results are AMAZING, and yet you still have a Hayabusa engine, and the aerodynamics of a Hayabusa, neither of which a liter bike is ever going to have.
