Wire a coil to the battery and then to a switch and then run a spark plug wire to a hot sparkplug in the pipe, mabey run some propane in the pipe ( if you dont want to play with the carb ), do this by getting a $9.99 propane torch from wal mart, drilling a hole in the pipe and stickin the torch end in the pipe and braze or sodder it in the pipe. A mount must be made for the bottle. When you want to flame, open up your torch valve and hit the switch. This may not be pretty but, it can be covered and made pretty.