cc's vs horsepower

[gunsavy]

can someone explain to me how 1000 cc bike can compete with a 600 cc bike I know in the early days of Moto gp those bikes were 500cc bit from what I understand they ridiculously fast. what is the conversion
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[TruWrecks]

They were 500cc 2-stroke engines. The 1000cc MotoGP bikes were 4-stroke. They 800cc bikes are also 4-stroke.

[afterhours]

in a race what maters is getting around the track....and sometimes too much hp can make that difficult. go to your local track, you will find F1, F2 classes......where 600cc bikes compete against literbikes, and 250cc gp bikes.

[AJAY]

+ 5 on the weight issue. It's a whole lot easier to move less weight around, especially if turns are involved.

As for power, you also need to think of displacement vs. time.

To use simple numbers, a 500 cc engine spinning 10,000 rpm is displacing as much as a 1000 cc engine spinning 5,000 rpm.

Your Busa engine tops out at 11,000 rpm.
The new Kawasaki 600 tops out at 16,000 rpm. (wow!)

The magic formula is

Horsepower = Torque x RPM divided by 5252

Small engines make less torque, but if you can spin them faster, they can make similar horsepower as big engines.

But torque, especially low end torque makes a bike fun to ride!

[dadofthree]

[jellyrug]

It is true that power is proportional to rpm x torque, but there is no compromise for displacement. A lot of of efficiency is lost in a high RPM motor, due to the inertia of moving parts and ability for the motor to breathe (aspirate) enough oxygen for combustion.

If you look at power curves, a 600 makes a lot less than a 1,000.

With a 600, there is enough power though to lift the front wheel in a launch from standstill, so it comes to rider skill. Weight is also very important during acceleration, helping the smaller bike.

One has to keep the revolutions up though with the smaller motors, different kind of riding.

The big difference with bigger motors starts above 140mph, as wind force is now more prominent than acceleration and rider skill.