I assume you are using the choke correctly to start the bike?
What do you mean you have a weak spark? How did you test it for being "weak"? What does the plug look like?
Did you measure the voltage at the battery with the engine running? That will tell you real quick what voltage you are putting out going into your battery and if the charging system is working appropriately.
And what do you mean by the starter drags? Running or turning over slowly? Have you cleaned all your battery and starter connections and ground of corrosion and made sure they are clean and tight?