ONE "GOOD" BACKFIRE

[wsachse@ncinter.net (Bill Sachse)]

I am helping my friend with a 71(?) midget and we can not get rid of a
backfire when you shift it.  The car is in good condition including:
overhauled engine with a mild cam, new throttle shafts in carbs, air
pump-gulp valve- check valve all in good condition, and no exhaust leaks.
The car letes out one "ggod" backfire when you shift it unless you keep the
revs up.  Please note that the problem does go away when the air pump is
disabled.  Any help wii be greatly appreciated!