Bonneville America Forums Forums Technical Forums Exhaust exhaust sound and pilot screw setting

So after 6,000 miles of tinkering I've finally noticed that the idle mixture screw setting affects the sound of the pipes. And it seems to do this throughout the RPM range. The further out (richer), the louder and boomier the pipes. I'm surpised it makes such a differene especially beyond the idle circut. Any of you gurus want to explain?

06 TBA. Freak, TBikes, 160s, TBS needles, 3 turns out on stock pilot jets.

I noticed a difference, too.

Lot's of crackling and popping on decell (the good kind) at 2 turns out, but no backfire.

At 2.5 turns out, had a little deeper rumble, but had an intermittent backfire on decell...I guess it sounded "richer" because it was, but the backfire went away when I screwed them back in, then 2 turns out again.

Experiment over.

I'll be pulling and changing plugs again this weekend or next, as I'm over 36k now, so I will see what's up with the plug colors after putting a couple of thousand miles on since the rejet. I know she has to be pretty close to spot-on.

The pilot screw doesn't just effect low range it continues to feed fuel through mid throttle. I think it was Phil who posted a good graphic on this that shows when carb circuits start to feed and when they taper off. and here it is

Thanks.