Motorcycle starts and revs but won't run?

I have a 2004 honda rebel 250, and it has a little trouble starting but i can get it started. When i rev the engine though, it starts to sound a little off and the whole bike vibrates like crazy. If i let off the clutch the bike pulls a bit, but it doesn't move if i give it throttle, like the clutch is burned out (but I think the clutch is fine).
Any suggestions as to what's wrong are highly appreciated.

Have you changed the engine oil lately?
Did you use motorcycle approved oil if you did?

May also be a bit of clutch-lag, so the cable may need adjusting/or replaced.

Start up the engine again, while at normal RPM in Neutral pull in the clutch lever without putting it into gear and listen for any sound differances. If a slight metallic thumping is heard before but not after than the cltch basket or the clutch plates are worn.

Does the problem happen when in neutral?
Try cleaning the carburetor.
Your carburetor has an accelerator pump.
When you twist the throttle, the pump squirts additional gas into the cylinder, to help the engine rev faster, to get the bike moving.
The pump has a rubber diaphragm which deteriorates over time.
The circuit has passageways as thin as a pin head and get easily clogged with bad gas.

First check the engine mounts are properly torqued.