Topic: Dyna S timing question on CB550

[The Machine]

I've timed it with a timing gun, set it at the F mark. When I rev the motor it stays revved for a little bit then slowly comes back down to idle. I know there can be many reasons for this but what would be the most obvious reason? I'll start with that and work my way through the list. Bike runs well, has power but sputters a little at 3/4 throttle.

[Scott S]

 Did you set it at idle or at ~2,500 RPM? I always set the advance for full advance, the II marks just past the F mark. I let idle timing fall where it may.

[Bodi]

Most likely is a vacuum leak at the carb spacers.

[The Machine]

Thank you, I set it at the advance setting seems to be doing a little better. I'll check for the leak, I've removed the carbs recently so hopefully that's the case.