I have a 1999 night rain so obviously im use to a lot of back fire but recently it has been doing it a ridiculous amount, also my hyper box will almost give a fluttering noise when i hit the throttle but only when first starting out. If anyone can give me some info on what the problem is and how to fix it, it would be appreciated

 

I would start by checking the Intake Manifold Seals as well as the overall cleanliness of the carb. Also, good to check spark plugs & wires for overall condition.

More info here: https://cv-performance.com/harley-cv...-tuning-issues

 

Thank you for the advice i will for sure check those things out