Backfire / exhaust popping

[olchris]

So where does the "Backfire / exhaust popping" come in to it... Sounded OK to me in the video, before i got sleeeeepy...

[mrtwowheel]

Just throwing ideas....Plug Caps. Can't remember if a plug has to spark for the light to light. Been decades since I used a dwell meter or timing light. Plug caps can go intermittent.

Scott

[CHUCK HAHN]

The popping comes in when riding at any steady speed. Climbs out and decells fine and no pops. I also have to consider maybe its sucking air in at the right muffler joint where the header pipe goes in. I got new OEM gaskets but theres still a leak. The metal pieces that go around the header pipe and the clamp then squeezes against the gasket are really weak and rusted. I may need to find some sort of heat proof tape to seal the joint up well.

[CHUCK HAHN]

Update.....Found a timing sight glass tool on Ebay for 20 bucks and did the dynamic timing and its spot on now. seems to have eliminated the backfiring thus far. Thats and going back over and rechecking the points gaps and the ballast resistance tests. All checks out according to the service manual.

[JSBail]

Update.....Found a timing sight glass tool on Ebay for 20 bucks and did the dynamic timing and its spot on now. seems to have eliminated the backfiring thus far. Thats and going back over and rechecking the points gaps and the ballast resistance tests. All checks out according to the service manual.

You may already know this but I'm just saying to make sure, if you're going to re-check your point gap and end up adjusting it a bit then re-check your timing again when your done.

[CHUCK HAHN]

Did that too. Im about sure its as good as its gonna get.

[jdvorchak]

FYI that dial at the back of the light is an advance dial. How you use it, on old distributor engines, is to dial the idle advance you want, say 7 deg BTDC. Then adjust your distributor until the timing marks line up at 0 BTDC. Some of the older cars were hard to read the advance scale on the engine. This "new" feature made it easier to set timing. Also helpful if you want to check overall advance. adjust the dial to max overall, say 43 deg BTDC at 4000RPM. Dial up 43 deg and rev engine to 4k RPM and read timing mark at 0 deg. Or adjust that dial until it lights at 0 deg and read your overall advance on that dial.

[CHUCK HAHN]

yeah...that light was set at 0 on the medial so there wasnt any induced advance or retardation. Then the bulb burnt out on it and I had to go buy another light...good times!!! RThat timing glass tool really is nice to have. can see the flywheel marks perfectly and adjustment was simple once I could actually "clearly" see the timing marks.