Fido_the_Cat wrote on 12/31/69 at 16:00:03:Having said that, does that mean that the white spacer is the 1/4 to 3/4 adjustment? Is the popping that I have a lean fuel setting not getting burned off at decelleration?
Thanks again, I finally got the muffler mounted trhe way I wanted. Looks factory. Sounds Distinct!
Yep, shaving the white spacer is basically the same as moving the clip on a "normal" needle up or down to a different groove and it affects the 1/4-3/4 throttle range.
It is the pilot jet and it's "pilot air adjusting screw" that will affect the backfiring issue.
There is a write-up somewhere that describes what happens that leads to backfiring, where the carb is concerned. Exhaust air leaks can also do it but this is the carb side of the issue. When the fuel/air ratio gets too lean (especially on deceleration with the throttle closed) it does not burn properly and thus leaves some unburned. It collects in the pipe and after a bit finally ignites, giving the
[glow=red,2,300] BANG [/glow] we all love and adore. Richening the mixture to the proper ratio enables a more complete burn which does not leave enough unburned fuel to collect in the pipe.
That is the quick and dirty of it.