Which bike is fastest - KTM RC8 R (V-twin) or Kawasaki Ninja H2 (in-line 4 cylinder)???

Fastest bike is Ninja H2

H2

Of course no doubt.. With super charger the H2 is much more faster than rc8r. H2 having 206 bhp with RAM AIR. and rc8r having 187 bhp.

The fastest one from both is the Kawasaki Ninja H2. The bike is the only one to have a supercharger in the motorcycle industry and comes with a 998 cc, 4-cylinder engine producing 207.1 BHP @ 11,000 rpm and 132.8 NM @ 10,500 rpm. The bike comes with a six speed gearbox and takes 2.5 seconds to reach 100 kmph from stand still. It comes with a 17 liter fuel tank and comes with Kawasaki supercharger for high performance. It comes with 238 kg of kerb weight and 130 mm of ground clearance. It can be bought in India for INR 29,00,000 and has a top speed of 300+ kmph whereas the KTM RC8 R stays at 287 kmph only.

Kawasaki Ninja H2 - Built Beyond Belief