I have a 2004 suzuki ltz400 that is making a popping noise at idle and when riding. It has a brand new carb on it' a new spark plug and fresh gas. Any suggestions as to to what it could be would be helpful.

 

Depends on what popping means...could be a lean condition or even a rich condition. What color is spark plug after going for a ride? Should be dark brown to darker tan for normal operation. If dark gray or black then rich, if light gray or whitish then running lean. New carb means nothing as it still needs adjusting to match engine. If an aftermarket carb then that could be another issue .

 

The spark plug is very black.

 

If it is black that means it's running rich correct?
So would I adjust the air/ fuel mixture screw?