popping on overrun

[Julian]

Guys

Continuing with the long process of bringing my 72 Fulvia 1.3S coupe back up to scratch, I have balanced and tuned the carbs, set the timing, set all the clearances (to factory spec) and the car now runs perfectly with only one minor problem. The exhaust is constantly ‘popping on overrun’ and although I suspect that this is down to the usual problem of air getting into the system, any advice / experience would be appreciated.

Thanks

Julian

[william]

I have the same thing. A slight barking sound when the throttle is lifted. Just sporty enough not to be anoying. On my car it is caused by the exhaust junction between the 2 in 1 downpipe and the first muffler. No amount of goo will close the joint.

[justin]

This is always air getting into the exhaust at a point where the pies are very hot, which enables the excess fuel that gets past the exhaust valves to burn quickly.
No air, no sudden burn, no pop.