Because they haven't got a scotoiler!
Its a very rarely known fact that the fitting of a scotoiler automatically sets the suspension correctly regardless of which bike, your weight, riding style or road conditions! Scotoiler themselves have been aware of this fact for many years but dare not publicise the fact for fear of reprisals from suspension tuners the world over. Last year, when a famous scandinavian gentleman discovered the secret to Scotoilers success, there ensued a tremendous cloak and dagger legal battle surpassed in it's ferocity only by the invasion of Iraq. Only now has the dust begun to settle on this best forgotten episode in motorcycle technological breakthroughs!
