Confirmed popping through intake, Timing off? Options

[corsepervita]

Ok - so I've sealed up all the potential exhaust leaks except the one possible leak coming from the back of my muffler which may be small - unable to tell.

However, I started noticing a popping noise. I recall it a few times when I first started driving the car but it was so small I couldn't really make out what the noise was.

The other day after fixing the exhaust I rolled down the windows and listened more carefully. The same odd "poof" noise I heard behind me was audibly from the engine area. I had my wife get in the car while the car was cold and blip the throttle while it was in neutral to see if it would do it again - it did. It was unmistakably some sort of pop from the intake. It's more of a "poof" than a loud "bang" ...

I've heard the noise before on my 924 when the exhaust was partially torn apart - but that was a HUGE lack of back pressure. So that kind of (lack of)back pressure wasn't there since the exhaust is complete, no leak at the heads anymore, and as well only a small one up near the muffler - but even then it's tiny.

I remember hearing that popping through the intake is either running too rich, timing off (retarded) or a huge exhaust leak.

Since the popping on decel seems to happen very frequently - and just as much so (sometimes more) after the exhaust leaks were taken care of, I'm noticing this more as well. Since decel popping would be culprit to a lean condition - and intake popping would be culprit to a rich condition (at least as far as I know, I may be off on that); My assumption would then be my timing is off? (since obviously you can't have both lol)

Wanted to bounce this off everyone here in case I'm crazy. Again - new to working on these little air cooled engines. I'm gonna go put it back up on stands tonight and crawl under and check.

A family member also suggested I may have valves that are too tight, but I recall Jim saying he already adjusted the valves and they were adjusted to the .006" mark they were supposed to be at. I plan on replacing the pushrod tube seals here soon - he sent me a procedure on how to do it (i also found a wonderful article on the forum about it) so I will end up double checking them anyway.

Any ideas? I'm gonna go get a pot of coffee going and go get it up on stands once I have a brew going and get acquainted with the car some more.