Not a lot to go on from your post, but I'll take a stab at it.
I would be rather surprised that a dealer wouldn't have fixed that under warranty, or that someone would put up with that without trying to fix it.
For any symptoms this could be as simple as setting the valves...should be real real easy on this bike. Check the plug or change it while you're there (Just have a fresh plug ready and keep the old one as a spare for next time if it's still good)
If it's tough starting and not idling much until it's warmed up, then it's your cold start valve most likely.
If it's dying after warmed up and not idling well at all or idling erratically then it sounds like a vacuum issue, possibly similar to what I had when I cracked the tube for the PAIR valve on my S200.
Could be intake side of course, but the PAIR's easy to check and ya gotta move it to set the valves anyway.
Can't recall what the new tube for the S was but it was under $50 for the repair parts. & only a mild PITA to fix (had to scrape and recreate one gasket)
