I have a single cyl bike that goes over 160mph and tries to wheelie out of your control at every chance. The vibration is way worse than a similar 4cyl. The more pistons, the less vibration. That is why luxury cars have been the homes of v12s and the like. Harmonics are more impactful inside the engine. Uneven firing of the cylinder is actually a feature to maintain traction in sport bikes, look up 'big bang firing order' for an interesting rabbit hole.