The motorcycles used in MotoGP™ are purpose-built – ‘prototypes’. MotoGP™ bikes are not available for purchase by the general public and cannot be legally ridden on public roads.
The maximum engine displacement permitted is 1000cc, with a maximum of four cylinders and a maximum bore of 81 mm – two -stroke engines are not allowed.
A maximum of seven engines can be used by each rider over all the scheduled races of the season. Penalty for infrigement of this means the rider will start from the pit lane, 5 sec after the green lights comes on at the exit of the pitlane.
Engine by Manufacturer
V4 engine: KTM
V4 90° engine: Ducati, Honda, Aprilia
In-Line engine: Yamaha, Suzuki
*L4 90° V Engine is rotated V4.
Comparison: V4 vs In-Line Engine
V4 engine makes more horsepower. And mostly, it’s about the crankshaft. A V4’s crankshaft is shorter than an inline-four’s, so it’s stiffer and stronger.
It also creates less friction because it runs on three main bearings, not five, the minimum required by an inline-four. And with adjacent connecting rods on the same big-end journal it creates less rocking couple. Even better, a 90-degree vee has perfect primary balance.
There are also pumping losses, which is the power wasted in pumping air through the engine from intake to exhaust. Up to 300 litres of air per second flows through a 1000cc engine at 18,000rpm, and a V4 crankcase layout deals with that flow much better than an inline-four crankcase, so the V4 loses less power through pumping losses.
So, a stronger crankshaft, less vibration and better balance allow designers to push the engine harder for more revs and more horsepower, with the added advantage of fewer losses through friction and pumping.
The 90-degree configuration – used by Ducati in MotoGP since 2003 and by Honda since 2012 – has a further advantage. It allows designers to use a greater variety of unbalanced firing orders – big bang, long bang and so on – in their attempts to produce a more rider-friendly type of power and torque.
This explains why Ducati, Honda, KTM and now Aprilia use 90-degree V4s, instead of narrower-angle vees in MotoGP – it allows them to create more horsepower and a better kind of horsepower.
A 90-degree V4 has several negatives. It is long, which causes headaches for chassis designers trying to keep the motorcycle’s wheelbase short for quick turning. Also, its rear cylinders take up a lot of space and create a lot of heat in a crucial area of the motorcycle. This requires clever work on frame, airbox, exhaust and fuel tank design.
V4s don’t enjoy a huge advantage on the straights, but enough to make a crucial difference during a race. At last year’s Qatar GP the fastest V4 was Marc Márquez’s RC213V at 218.7mph/352km/h, about 2mph/3.5km/h better than the fastest inline-four, Joan Mir’s Suzuki GSX-RR.
At Mugello, the fastest V4 was Andrea Dovizioso’s Desmosedici at 221.6mph/356.7km/h (official speed record), around 3.5km/h better than the best inline-four, again Mir’s GSX-RR.