Motorcycle Repair: 1992 evo engine, stock carb, mikuni

Question
rear cyl seems to have slaping sound instead of thump////motor seems to top out at about 90mph. im replacing stock carb with s&s E. pipes are 1/34 drag..if i go into engine/what should i change//////// electric  glide

Answer
start off by changing the exhaust system. the 1.3/4" drags are killing any horse power or torque the bike had and is not good for your motor. That is where I would start!!!!
Sorry to here you are putting a S&S carb on your bike. I would install a Mikuni HRS 42 mm it is twice the carb then the old S&S. I would first do this before going into the engine.       Johnny