http://www.yamaha-motor.com/sport/products/modelfeatures/6/0/features.aspx

:dunno

quoted from Yamaha website:
Crossplane crankshaft technology proven in victory after victory on MotoGP machines provides a high-tech uneven firing interval. Unlike typical in-line-four engine design, where the two outer and two inner pistons move together in pairs with 180?intervals, the crossplane crankshaft has each connecting rod 90? from the next with a unique firing order of 270? ?180? ? 90? ? 180?. This overcomes the inherent fluctuations in inertial torque during each engine revolution, and the accompanying peaky torque characteristics. Instead, compression torque continues to build, giving the rider more linear throttle response with awesome power and traction out of the corners.

 

http://www.yamaha-motor.com/sport/products/modelfeatures/6/0/features.aspx

:dunno

Thanks! But I couldn't quite figure it out from that.

 

If each character is a 90 degree rotation of the engine...

Flat plane crank engine fires like this:
X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-

Cross plane crank engine fires like this:
X--X-XX-X--X-XX-X--X-XX-X--X-XX-X--X-XX-

Yamaha put out this video to explain it musically.

http://hellforleathermagazine.com/2008/09/details-2009-yamaha-r1-crosspl.html

Or if you're more visual:

http://www.sportrider.com/bikes/146_0812_2009_yamaha_yzf_r1_fz6r/photo_07.html

That only shows the firing timing, but it's a standard 4-stroke engine, so you should be able to interpolate intake/compression/power/exhaust from that.

So it's like you said, they "split it up". It's not all that confusing. It's a lot more even than you'd think.

 

If each character is a 90 degree rotation of the engine...

Flat plane crank engine fires like this:
X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-

Cross plane crank engine fires like this:
X--X-XX-X--X-XX-X--X-XX-X--X-XX-X--X-XX-

Yamaha put out this video to explain it musically.

http://hellforleathermagazine.com/2008/09/details-2009-yamaha-r1-crosspl.html

Or if you're more visual:

http://www.sportrider.com/bikes/146_0812_2009_yamaha_yzf_r1_fz6r/photo_07.html

That only shows the firing timing, but it's a standard 4-stroke engine, so you should be able to interpolate intake/compression/power/exhaust from that.

So it's like you said, they "split it up". It's not all that confusing. It's a lot more even than you'd think.

Great post! Your second link gave me exactly what I was looking for and the first provided and interesting view of whats going on.

It's interesting stuff for sure. I guess the question is how long till you can buy an aftermarket crank and cams for earlier years.

 

so what they mean is that it first fires on 270, then 180 from that it fires again and so on. which would translate to 270 450 540 720.

 

http://www.crash.net/British+Superb...itish+Superbikes/Feature/3632/1/exclusive_virgin_big-bang_secrets_revealed.html

Big Bang explained

 

Thanks guys!

 

thats pretty cool, didnt know that. so basically sounds like virgin yamaha, basically i 3 cylinder. 1 fires, then 2 and 3 at same time, and then #4. i always thought that 1 an 4 fired as one, then 2 and 3 fired as one, making it basically like a two cylinder, but reading that shows that it has excess stress on parts. good read for sure

 

Not at the "same time", really. Just 90 degrees apart.

 

Virgin had a big bang, 2 cylinders fired at the same time. They tried 2-2 and kept breaking primary gears and warping cases. So they did the "priming" 1-2-1 but that "2" was 2 cylinders at the same time. Worked so well the FIM rushed a rule to ban big bang conversions.

The 09 R1 is not a big bang, you don't have 2 cylinders firing at the same time as it was already posted. It's considered a "long bang", totally different. Kawasaki is said to be developing a true big bang using the 2-2 firing order with an electric motor that will also could be used as KERS and ACG. Ducati used a "twin pulse" on their gp6 990cc motogp bike, which is now used on the d16rr. That's a v4 with a firing order where 2 pistons fire within 90 degrees, then rest, then 2 others fire within 90 degrees again.

 

okay.. thanks.. that even explains it little more. just cool to me. i like the idea of something different. yea i remember seeing something on added balancer to counter the vibes.

 

A true big bang engine has all cylinders firing at the same time. Since they make more torq at the expense of HP, they're used in hillclimb vehicles and pullin' tractors.