exhaust backfire at idle

[356robo]

Before service, no backfire.

After adjusting valves, installing pertronix, setting timing at 2 degrees btc at 900 idle and 30 degrees at 6,000, installing new plugs, I now have periodic backfire through the exhaust at idle.

The webers were not touched. The exhaust was not touched.

Anyone have any ideas?

Thanks in advance,

Rob

[red 2.7]

double check your spark plug wires 162435 if that's good popping at the exhaust is rich thru the carbs it's lean. Blow out the idle jets and go from there there are a million threads on tuning Webers.

[356robo]

Red2.7,

Thank you for your response, but I don't think its a carb issue. I did not touch the carbs.

All I did was:

Adjust valves
Replace plugs
Install Pertronix
Set timing at 2 degress after tdc @ idle and 30 degrees @ 6,000 rpm

Today, I'll check all wiring connections and make sure cap and rotor are aligned properly.

Rob

[356robo]

red2.7,

Thanks for the info. I checked the distributor connections and found a couple loose. Must have happened during movement.

Thanks again,

Nothing like the sweet sound and feel of a freshly tuned 911.

Rob