Motorcycle Repair: how to tune, harley 883 sportster, carburetor

Question
hi I just bought a 1968 harley 883 sportster and i am getting a backfire and some hesatation on take off what do you think is wrong  

Answer
Could be lots of stuff. Just put in a new set of plugs for starters.  Carbon on the plugs or leaks at the exhaust connections to the head are the most common causes of backfiring, unless of course your ignition timing is off.  The hesitation is probably either ignition timing or carburetor jetting, especially if you are running a carb with no accelerator pump.  If you are running a carb with an accelerator pump make sure it starts squirting as soon as you twist the throttle.  All of this should be taken care of with a proper tune-up.