This is one of the few plastic parts on the DR650 that can ruin your day if it breaks or fails on you. This gear helps drive the oil pump to circulate oil throughout your entire motor, without it, your motor will fail entirely. The idler gear is not known for being a common failure point in the DR650 motor but, it has failed riders in the past. Usually in the form of a broken gear or stripped teeth. Upon inspection, look for any kind of crack, chipped or missing teeth on the gear. It is not a complicated repair to swap an old gear for a new one, as the best time to replace it is when you've opened up the clutch side case cover for another repair i.e., (NSU screws or clutch hub bushing replacements). This is an O.E. Suzuki part.