I changed out the muffler today and now the moped stalls when I pull up to a stop. The moped is 1993 Tomos golden bullet A35 with a 70cc kit and an amal 15mm carb. The old muffler was a two piece biturbo. It had lost its packing and the tail pipe end broke. So I replaced it with a new biturbo (same as the old) rear half (expansion and muffler).
I am guessing the problem has to do with reduced air flow through the system and maybe a back pressure problem. Should I adjust the carb to change the air intake? Or maybe adjust the idle. Any thoughts?