Everyone brings up interesting points. My buddy bought an '05 Busa and I got an new '04 ZX12.
Many differences boil down to personal preference, regarding ergos, feel and where the motor pulls.
Both are great bikes and I fully agree that it's rider vs. rider in most contests, not bike vs. bike.
We drag them, roll them on and canyon ride them. The Busa has about 10ft/lbs more tq, the 12 about 10 hp. How you ride it, and where you choose to punch off (rpms) makes or breaks roll-ons.
From a stop, the Busa jumps out and then the 12 starts running up on it as the speeds increase. We have yet to hit the limiters on either bike.
But, from a second gear (mid-range) roll up to about 170 they were damn near side by side. If I let the Busa punch off at low speed and I'm up a gear, he squirts off. But if I know it's coming, I run a gear lower and can pull him. So knowing each bikes strengths and weaknesses is critical in contests between the two.
I'm taller than he is, so I like the 12. It's a taller bike and has more leg room for me. In addition, I can't see the top 1/2 of the dash on the Busa due to the windscreen.
Tranny feel is also personal preference. The 12 is much more "buttery smooth" , the Busa has the nice mechanical notchy feel that lets you know it's solidly in gear.
The Busa's motor pulls down low, the 12 up high, as said before. Coming off a ZX9, it's power band suits me fine and I don't mind rowing the box a little bit to get every bit out of it. Though many like the torque of the 1300cc motor and the way it freight trains without a downshift. The 12 makes you work a little more in that regard.
The Busa's hydraulic clutch is not as good as the 12's cable actuated unit. I have never had a bike with a more linear, smooth and predictable engagement point. Though, it does have a heavy pull at the lever. Again, depends on what you want to do with it.
I have the latest version of the 12 with radial brakes. (The bike pictured at the top of this thread is an '02-'03, as it still has the six-piston Tokicos).
I think the Busa has better brake feel stock vs stock. My major complaint with the bike has been that it has a spongy front brake and "weak" back brake. I've bled the brakes and I believe the problem is an excessively soft pair of brake front brake lines. Once they are clamped and the excessive travel taken up they are strong and have a good feel. The Busa's brakes are firm, strong and hit right now! Like my last bike's. But, my friend also has prematurely locked his rear brake, so perhaps the softer rear brake on the 12 is a good thing? I'm not sold that the new radial brakes are an improvement... we will see when new lines go on.
The 12's motor seems smoother. Cosmetics preferences are personal. The Busa stock feels much more nimble in the handling department because the goofs at Kawi put the monster Huge 200mm Dunlop on the rear. It felt very heavy and didn't like to transition. I have since put on an 190 and it feels like a totally different bike. Feels like it lost 50 lbs and falls into turns and is much more resistant to standing up and running wide out the exit of an apex.
I like all the Busa's bells and whistles on the dash. I'm a sucker for all the gimmicky stuff like the fuel consumption read outs, and I think the crisp blue and green dash indicators are more classy looking than the Kawi's. Same goes for the nice paint on the inner fairing pieces.
We have yet to go on a real long ride together. We keep buzzing around and hitting the strip every week before we can go through a full tank cycle to check mpg. Both seem like they'll hit between 37-40 if we are ever nice to them.
Speaking of tanks, I like the Busa's "real" tank and it's paint. The 12 has the "fake" tank. It's plastic and they apparently use a different paint on it, as it is soft and easy to scratch and buff with you're legs and a tank bag.
Uhhhh, I think that was it. Sorry for the run-on. But thought you would like to hear the straight scoop from someone who actually owns, commutes and races on the latest version.
Bottom line, each bike has it's idividual pro's and con's. Each bike is an outstanding machine and probably exceeds the capablities of it's owners 90% of the time. Get one and then start working down the list modding away what ever you don't like.
One this is absolutely clear. The reputation earned by the Busa early-on has snowballed to God-Like status. Any school girl can tell you what a Hayabusa is! No one even seems to notice the 12R, or know anything about it.
Example; My Kawi Concours riding neighbor strolls over to look at my new bike. He looks at it briefly and says "You wanted a fast bike, you shoulda got a Hayabusa". I didn't even waste my breath explaining that they are virtually identical in performance... nothing will change the minds of those who have read otherwise, despite me just getting back from canyon riding and racing both all afternoon.
On the up-side, my Silver bike is kind of bland looking, and has not received any kind of un-wanted attention either. I pull up, people look at me like an older guy with a tank bag, and they are soon shocked when they see my tail light growing smaller on the horizon.
Oh, and my bike seems to put much more weight on the riders wrists, where his puts more weight on you're butt. But he has bar risers and I guess they will be added to my list of "must-have" goodies as well.
I now must appologize for the double run-on.
Shoot me specific questions I'll give feedback or test it out against his bike.