| It's critical that the cam belts be replaced every 12,000 miles. Space limitations on Ducati's require the use of smaller diameter pulleys that cause the belt to flex more than large pulleys used in automobile engines. Further, Ducati uses a small diameter back-side belt-tensioning idler pulley arrangement that causes the belt to flex in the opposite direction on each revolution. This design approach results in an even greater angle of belt flexing, requiring the use of a stronger reinforcement fiber to prevent fatigue failure. The original drive belt design often failed before the first 12,000 mile replacement interval so Ducati switched to a Kevlar fiber reinforced belt. These are interference engines, which means that a belt failure results in a catastrophic collision between the piston and valves. |