In the cases that I have read about when a belt failed on a 650 and the cause was tracked down it turned out some other part failed first causing the pulleys to lock up and ruin the belt. Those causes have been traced to stopper bolt failure, bearing failure due to water entering the ECVT, foreign matter getting into the ECVT usually due to rodents, input spline failure, and failure of the friction pads inside the primary pulley. Sounds like a lot but only a very small fraction of 650 owners ever have a problem with the ECVT.
Suzuki made a change to the input spline after the 04 model that solved that problem. Periodic inspection and replacement of the stopper bolt solves that issue. Not riding the bike in water deeper than the floorboards solves the water incursion problem. If you store the bike in an area that has problems with mice and other rodents there is a simple modification that can be made to cover the ECVT exhaust port to keep them out. The problem with wear on the friction pads inside the primary pully has only been recently discovered. I've only heard of a couple of mentions of it so not much data is available.
Thanks Buffalo... After having 2 cvt's replaced, and prepping for a court case, I have become quite educated on this issue, and you nailed it. The show stopper for the big "S" will be the fact that they went with a thicker bolt, along with strength enhancement...
