I am trying to fix a friend bear tracker it is backfiring real bad and is hard to crank spark fire seems good can anybody help.[img]i/expressions/face-icon-small-confused.gif[/img]

 

A few things to check would be, the compression, clean the carb really well, check the air to fuel screw, check all gas and air lines. Check the choke to make sure its not stuck. Check the filter. Check all electrical connections. Maybe some others have some different ideas.