Topic: Weird popping noises?

[LoopsAndLogic]

Just a little symptom that I would like the answer to.

I have a Stock 400F with a Mac muffler, stock headers, stock air box and filter, and stock jets.

The needle jets were raised one clip for a richer midrange, but the problem I'm having is when I
decelerate with the clutch engaged, I can hear in the tone of the muffler faint and sometimes mild popping/miss firing sounds.

Is this normal? Someone told me that this indicates a lean mixture. But my low end and midrange feel great!
 I never go WOT on the old girl, so I never worried about the main jets.

Any insight on this is appreciated

LL

[mystic_1]

Popping in the exhaust on deceleration with the clutch engaged can indicate air leaks in the exhaust.

mystic_1

[LoopsAndLogic]

Really, well I'm glad I'm replacing the header gasket rings with my Newly painted Dupli-color 1200F painted headers.

(That paint is awesome just in case someone was wondering)

The old ones looked like they were pretty much toast cause the casting on the motor head was Very slightly black
by the header openings.

Any other things that could cause this?

Thanks for the reply

LL

[scondon]

   When you close off the throttle to decelerate your carbs are feeding mostly from the idle circuit. Try richening the circuit 1/4 turn at a time until popping diminishes. It can often be just one carb that is running lean so best to set all four using method found in manual as they might need varying turns out to run equal.

   Check for air leaks in the carb rubbers between carb and cylinder head. And retighten the headers if you haven't already. Once installed and run through some heat cycles they often need retorquing.

[DJ_AX]

I wondered what caused that... just 15 minutes ago in fact  ...
I love that sound ... especially in rush hour traffic.
but hmmm.. have to check my carbs settings ...
Oh yeah... that's getting much closer on my to do list now anyway... 

[LoopsAndLogic]

This is actually the first time that I've come across this.

So, check the header gaskets and make sure the exhaust system has no leaks.
 Adjust or check the idle mixture screw...AKA, the air mixture screw on the side of the carbs.
And check the carb boots on the manifolds.

Should I use the old method of using some WD40 and see if there's a rise in idle???

Sounds good, and hopefully I'll find this problem and diminish to the ends of the earth. Ha ha!!

Thanks

LL