Umm....without knowing the cause, don't know why you would consider a gas additive. It's a machine. Things change. Things go wrong and come out of adjustment. For myself, I like a good-running machine. I'd do the dealer thing and make it right.

It isn't the battery situation. Something else has happened. Bet it's small and easy to diagnose for an experienced tech. Maybe even cheap. Wouldn't hurt to ask dealer about it and decide after receiving the answer.

Go a nice ride, there. Make it right would be my suggestion.

Thanks, Asolo. I just thought it was carburator gum-up or something similar, since it sat for a few weeks while the battery was down. It ran perfectly before that.

Kt

Usually, the cause for backfiring on closing the throttle is caused by the mixture going lean, not so lean it won't fire, but lean enough to retard burning and is still burning when the exhaust valve opens. In this case, it should also backfire on a downshift used to slow the bike.

You did not say what year of bike. My experience ends with carbureators. I did not own a bike with electronic engine management and that is a different can of worms.