Rattle at shutoff?

[chris in va]

I know very little about this bike, so maybe this is normal.

For about a second after shutoff I hear this rolling rattle sound in the engine like a gear is still spinning loosely somewhere. 

Also first gear tends to make the whole bike shake like crazy from a dead stop, almost like only one cylinder is firing...but I know both are popping.  Definitely enough to make the bars dance...like a Harley actually. 

[scratch]

Rattling - don't know; I'd have to hear it in person; not normal though.  If I were to conjecture, I'd say camchain, but it might be dependent on mileage.

Shaking like crazy from a stop - slip/feather the clutch some more, but give it more gas at first and get the rpm's up (~3,000rpm).