Getting back to that starter sprag clutch, whatever lube you're using in the primary (on advice from these Forums I use Type F Automatic Transmission Fluid, though the manual calls for 10W40), you might do well to add another 400 or so ml, or about a cup and a half, above that 420 ml level of the fluid level screw to better bathe that sprag gear. It seems there was some factory service advisory that went out some years back to that effect. It didn't save mine, which went tits up at about 9,000 miles, though very rarely used, but might help forestall the inevitable crunch with yours... especially if you NEVER use it.