1971 bus missing on #1 at low rpm

[whc03grady]

Not mine, but good folks we know. They're in Mexico.
Type I with dual Kadrons and a 009:
http://bodeswell.org/2010/04/06/3917/#comments

[Amskeptic]

Not mine, but good folks we know. They're in Mexico.
Type I with dual Kadrons and a 009:
http://bodeswell.org/2010/04/06/3917/#comments

Very possibly you have an intake manifold/port leak at cylinder #1. This lean condition causes a misfire at idle but cleans up at higher rpm. You can adjust the carbs and be satisfied with synchronization between banks and still have this issue. Plug color would tip you off. Check for leak with cool engine and a spritz of WD-40, if idle changes, you have a leak. It is not just the gasket. Aftermarket manifolds are famous for warping.

It should be noted that if you have a balance pipe between the front pair (otherwise known as a brake booster circuit) you can also have a lean condition shared by #3 and #1 because intake strokes are scavenging balance pipe air instead of drawing in fresh mixture.
Colin

[whc03grady]

Thanks for offering that, Colin.