The frenzied speculation about the new 800cc MotoGP bikes came partly to an end on Monday, after both Yamaha and Ducati unveiled their 800cc prototypes at Brno. Ducati's bike had been seen previously, but Monday was the first time that Loris Capirossi had had a chance to ride the new bike. Amazingly, Capirossi lapped within 1.4 seconds of his 990 time, on his very first outing on the bike. It looks like the bikes are going to be close to the 990s almost from the start. This was also Valentino Rossi's first time aboard the new Yamaha 800. Overall, the bikes looked fairly similar to their 990cc predecessors, with one or two minor changes. The Yamaha looks sharper and slimmer than the 990, the chief difference on the Ducati is the revised exhaust, with the final section being longer and a two-into-one, rather than two separate pipes.
Pictures are popping up all over the internet, so I'll refer you there to get them:
Crash.net has a story on the Ducati, and a story on the Yamaha.
MotoGP.com even has some videos of the Ducati and Yamaha.
The biggest difference between the 990s and the 800s is the sound they make. The 800s sound like they are revving a lot higher, may be up to 2000 revs higher than the 990s. Interesting times lie ahead.
The 800s are being introduced as a result of a rule change in MotoGP for 2007. Capacity of the four stroke bikes is being reduced from 990cc to 800. The reasoning behind this is to make the bikes slower, and therefore safer. But with Capirossi already a second and a half of his 990 time, this argument doesn't look like it will hold water. Another change, maybe down to 500cc, which is rumored to be Honda's ultimate aim, may not be so very far down the line.