My friend has a stock 1998 Fatboy and I have a 1997 Fatboy. He has a CV carb. I have a Mikuni HSR 42. He has Vance and Hines short shots no baffles. I have short shots with slipons. Other than the exhaust why does his idle so much more like an old Harley? On his all you hear is that sweet popping sound.

both bikes are other wise stock. I think only difference is carb and I have screaming eagle box under seat. Before anyone says “it’s idled too low” even if I turn mine down it doesn’t sound like that.

His bike has idle set too low. Your bike has idle set too high. The different exhausts and baffles will make a big difference.

I know you said the internals of the engine are stock on both, but it kind of sounds like he may have a different cam.

besides your idle being slightly high, you might be running a tad on the rich side, but only an afr meter can tell for sure, or an inspection of the spark plugs. It wouldn’t hurt to compare the plugs of both bikes out of curiosity

the different carburetors usually mostly affect throttle response and acceleration but it is possible to affect idle. Your bike almost sounds fuel injected

it is mostly the difference in exhaust and baffles though, as that is the primary thing that affects sound

I have an AFR gauge on mine. I’m idling around 12.5. Maybe a little rich?

Sounds like two different idle speeds and the obvious different exhaust

His idle is turned down to get that potato sound. Probably about 8-900 rpms. Yours is higher, about 1100-1200, where it’s recommended for charging and oil circulation.
His bike is only charging when he’s moving. Sounds good but not good for the engine.
JMO YOMV

Sorry. Let me clarify. I meant more of the idle pattern. Not the actually tone.