I have an engine light that just came on, there is black smoke out of the exhaust [lots] ,back fires and is very hard to start. Any input would be great Thanks...

Key on switch on engine off
Slow five count; roll throttle to wide open
Hold throttle wide open for slow five count
Let throttle snap shut
Cycle kill switch
Start bike

Before doing this make sure that the battery conections are clean, and tight

You may have already fouled a plug; so clean, or replace plugs before restarting

I had a similar problem with my 05 vegas. It ended up being the engine temp sensor.Threads into the rear cylinder and costs about $20. Id try what kevin said first though.