MOTOGP » Yamaha's engine strategy explained

So Yamaha gives support for both motors? Why not just give Tech 3 the old, and the new when it's ready? Is it if the new doesn't work out? So Rossi doesn't have to go back to the old 07 but have at develloped 07 ready.

My guess is they keep developing the 'normal' engine as a backup,
in case the pneumatic valvespring engine isn't reliable enough. So Tech 3 benefit from that too.
I'm very happy that they decide to press on with the new engine, it means they are committed.

When the say "developed the old engine" I bet all there've done is tweek the ports/head, maybe refined the exhaust, definatly worked on new software.

I gathered they altered the bore/stroke though Furusawa admitted they were already very close to the critical piston speed
what was it 17 m/s? I forgot the exact number

I think i read in rapid bikes the Triumph 675 piston spins up to 17,18,19m/s or something like that, Id ssumed a motogp bike would beat that for sure????

17 m/s is the figure I learned in Engineering school, it probably didn't apply to racing bikes
The limitations are probably set by the materials used for pistons and treatment of cylinder walls.

end of last season yamaha said it wasn't goin to carry on development with the pneumatic engine,so why the u turn,yamaha dont like u turns it took rossi and burgess to convince them to go to a 16v head and dump the 20v the season before.
interesting thing is that i've read that schwantz is lined up for a suzuki team next year as manager
yamaha know that the suzuki was stronger than them last season and that rossis contract expires at the end of this season

17 m/s is quite old.

Even an R6 exceeds 22 m/s. A MotoGP bike could go up to 24 - 26 m/s!!

Any one knows the stroke of one of the GP-bikes?

Example: 2008 spec R6:
stroke: 42.5 mm
1 rev : 2 strokes
max. e-speed 16000 rev/min = 267 rev/sec

42,5 mm *2*(16000/60)[rev/s] / 1000[mm/m]= 22.7 m/s

Thanks Harryx,

Ther you go. Proves what an old fashioned guy I am like I said the number didn't apply to racing bikes...

Kevin Schwantz is one of Valentino's idols (besides the late Norick Abe), you never know.
This is the year of truth for Yamaha I think.

Hey Morgue, like I said; Stoner will have to work for it this year. Only at the IRTA test in Jerez we'll know more about the realistic potential of the teams.

But still, if the usual suspects stay rubber down and don't get into blowing up parts of their bikes, then a lot of them could get really close. Consistency was the word in the last 2 years and I'm sure it will be the case even more this year. I mean losing your points once could throw you off for the rest of the year.

(Actually 17 m/s is for cast iron engines :blush At a certain point the instantaneous piston speed can get so high (> 40 m/s) that aerodynamically and inertia wise you get in to "trouble".