The fuel supply is a gravity feed system. If there are any problems downstream, leaving the petcock on will most certainly exacerbate these issues. I always turn off the fuel when I am done riding for the day. It costs me no more than a moments embarrassment when I forget to to turn if back on...
The Nology coils are a darling. Some swear by them, some claim snake oil. Do some research to decide is my best advice.....
