Why does Rossi's M1 sounds like a V4???

How may a inline sound like a V4???

Only Rossi knows but there I sit glued to Speeds rerun of the African
MototGP... but this time around I'm not throwing my socks at the screen
and curing Yamaha... I'm concentrating on the sound of Rossi's M1 inline
4... by gosh it doesn't sound inline-ish at all... no sir... rather the
M1... going through the gears... sports a distinctive syncopated beat...
it sounds a like a V4... WHAT??? OK even as Rossi gives it all the
berries it growls in place of the customary high pitch scream inline are
noted for... M1's idle is also different... listen when Rossi parks next
to the tires and gets off and sobs with joy... (you're all heart man)...
the engine ticks over with a blat blat syncopated beat... it's like
nothing I've ever heard coming from a inline 4 before...

What's Yamaha secret???
I think Yamaha rephased the crankshaft from 180 to 360 and the new M1
fires like a big band parallel twin... anyone???

BTW if you got a way to post a sound file of Rossi's M1 from South
Africa... please do...

Larry L
94 RC45 #2
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If it wasn't for us the fast lane would rust...
V4'S are music to the seat of my pants...
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http://www.yamaha-racing.com/motogp/bikes.asp:

"the YZR-M1 will continue with its in-line four-cylinder engine layout,
but with a revised firing order to improve predictability and drivability."

It's probably more like a 270 degree firing order then. You'd need
uneven firing order to get the syncopated sound.


Eric

 

Yeah, that's what I keep reading in bike mags. Everyone suspects that
Yamaha changed the crankshaft/firing order. It could be 360, it could
be something else entirely if they threw in a counterbalancer, but I
don't think anyone outside of Yamaha knows for sure. They did this to
help with traction powering out of corners, because (as I'm sure you
know) unevenly spaced power pulses let the tire grip better. Whatever
they did, it apparently works.

I'm curious if all the M1s got this treatment, or only Rossi's. And
I'm waiting for the debut of Yamaha's 2WD system on the M1.

-Gniewko

 

Sure... thats the case... the motor is more tractable that way.. a wider
dead band between power pulses makes the back end stickier.

Phil Scott

 

its not a valve issue... its firing two at a time, gives a 360 degree
dead band between power strokes, so the rear is more tractable, it has time
to grab traction between power inputs.

 

Thats probably close...you would get the dead band for tractabiity and a
two pulse power input to the tire patch that way...that would indeed be a
lot more tractable than other arrangements... even the 360 crank.

Phil Scott