Last year, I noted that cranking speed on my '04 V11 was slowing significantly. With a charge, all was fine. However, I noted that the rectifier has a multi-pin connector at the left front down tube on the subframe. Rather exposed to weather. I undid it and cleaned the terminals with contact cleaner on a pipe cleaner, blew it our with air, then applied Caig De-oxIT and snapped it back together. All is well since. Water from rain or washing runs into the connector and corrosion begins. It doesn't take much before resistance rises. Anyway, as easy fix if that happens to be the trouble, and a maintenance item if not.