First Rob, now you! I may have to start looking at the current black market value of kidneys since I would love an upgrade from my F650 but there are not many bikes I'd consider an upgrade that's worth the $ aside from the big KTM's, and I can't afford the big KTM's!
Get a skid plate and some engine guards on that beast and lets go for a ride! (so I can take it for a short test ride obviously!)
When in doubt, gas it. It will either fix the problem, or at the very least end the suspense.
07 650GS / 05 DRZ400S / 72 CB350 (that hasn't run since shortly after I bought it)