Motorcycle Repair: 1984 harley FXRS, harley fxrs, variable venturi

Question
RECENTLY BOUGHT A '84 FXRS THAT HAD NOT BEEN RIDDEN FOR THREE YEARS. IT WILL START AND RUN BUT DOES NOT IDLE. IT BACKFIRES AND BLUE FLAMES COME OUT THE BUB EXHAUST PERIODICALLY (I LOOKED INSIDE THEM AND THEY ARE HOLLOW TUBES, NO BAFFLES/MUFFLERS). IT ACCELERATES AND HAS POWER WHEN RIDING. ALSO, IT HAS A LATER MODEL CARB WITH THE VACUUM ACTUATED VARIABLE VENTURI. ALSO, IS IT NORMAL FOR EXHAUST PIPES TO BECOME RED HOT NEAR THE MANIFOLD? THANKS, RAY  

Answer
It won't idle probably because the low speed jet is clogged.  Clean it out with an .018" needle drill.  Yes the pipes will get red at the head but only noticeable at night, or it's running too lean, or there's a leak at the head.  Backfiring is also common with no baffles.