Check the spark plug.  That was my problem.

When you are trying to start it, are you using the choke or do you just crank on the battery till it fires?  When you go to start it, do you have the petcock in the run position?

When my bike was hard to start after a long period of storage, I found that putting my fuel select switch to PRI would reduce the amount of cranking necessary to get the bike fired.  I also found that I had a slight leak in the vacuum line leading from the petcock to the carb.  That leak kept the fuel from being delivered in proper quantity when I was trying a cold start.  When I replaced the line, the problem went away, but I would still put the selector in PRI position for cold starts.

You only need the PRI for a couple of seconds (10-15).  All it does is put some gas in the carb fuel bowl.

For me, in the summer, no choke and a little throttle.
           in the winter, no throttle and some choke.

Whats all this noise about "sitting a few days"? Never heard of it.