Popping is a sign of running lean.
Did you change exhausts, frequently if you put a good low back pressure exhaust on a Virago it will run too lean and lay down and pop. Cure is a jet kit.
Check that the intakes are sealed correctly.
Make sure all vacuum lines are all on and none are cracked.
Ride it like you stole it......
1991 XV750
Corbin Seat
Customized Stock seat with rear saddle seat
1100 back rest with custom back rest pad
Yamaha windscreen
Yamaha Virago saddle bags.
Corbra Jet kit
Vance and Hines exhaust
LED rear turn signals.
Yamaha Rear Rack
