[Flieger]

What do you mean torque vs. effect? By effect do you mean power?

An engine with little torque can make loads of power if it spins fast- like a sportbike or an F1 car.

Torque comes about by two means. Inertia torque and gas torque. Gas torque is the actual force due to the combustion pressure. Inertia torque is the torque that remains after the combustion has stopped and is due to the momentum of the system. A heavy or large diameter flywheel has a lot of inertia and therefore lots of angular momentum. The reciprocating pistons and the rods travelling in general plane motion also have momentum and cause a force on the crankshaft because impulse = change in momentum. Impulse is force times time. The force varies with the orientation of the crankshaft throw and the changing leverage.

At high rpm, the inertia torque dominates the gas torque and this is where a properly balanced crankshaft really shines in smoother running. At low rpms, gas torque dominates and the firing order is more important.

Because of these effects, Yamaha used a cross-plane crankshaft in its YZF-R1 sportbike with its inline 4. The firing order is crazy uneven so it fives up some top end horsepower. At mid-throttle openings, the power is smoother, though, because the gas and inertia torques are more balanced. This does not overwhelm the rear tire and allows smoother drives off corners and wears tires less. Ducatis with a big L2 have a big bang firing order which makes huge torque and then goes quiet for a revolution to allow the tire to catch up. Sort of like pumping the brake pedal to stop lock-up. They are notoriously hard to ride but have crazy top-end horsepower.

Some race riders can feel the Yamaha's lack of agility, however. It is due to the necessary heavier, stronger crankshaft which has more inertia, angular momentum, and therefore a greater gyroscopic stabilization effect on leaning the bike through a turn.