Serowbot wrote on 09/17/08 at 18:19:11:You can get "backfires", afterfires from being too rich also. And your jetting is on the rich end. Seviersavage is referring to the idle mix srew on the right side of the carb not the idle speed screw on the left, by the choke. Your idle mix screw may be blocked off by a brass plug, if so it must be drilled out to make adjustments.
"Pop, blat, wooble-wooble, blat" type sounds are quite normal for a big thumper engine on deceleration. "Kaa-BANG!", gunshot type sounds are not good and you should try to reduce those.
The idle mixture screw has not been drilled out.
It's mostly "pop, blat" type sounds with only the occasional "BANG". Perhaps it's normal. Would a recording be useful?
Quote:My jetting is 150#/50# and I have similar mods to you. I am at 2500ft elevation in a dry climate, and that makes a huge difference in jetting. What is your elevation and climate? Heat, humidity, and elevation will make you run rich. Dry, cool, sea level will make you lean.
Elevation: 505 ft
Climate: "humid continental climate zone" is the technical term. Not quite as bad as Seattle, but close.
Rochester, NY to be specific.
-Dwarf