1986 Magna 700 idle problem

[86MAGNA]

Hello,

I have a 1986 Honda Magna 700 with around 10,000 miles.  It has always run great - until recently.  I just suddenly started dying at idle.  If the throttle is kept higher (or blipped) it will run, but if allowed to idle it will die.  It seems to run ok at 2000 rpm or above (although it seems more sluggish on acceleration that before).  I have checked the plugs (all look great), pulled one lead at a time while running and each cylinder is firing, changed fuel out, changed air filter, checked the fuel filter and eventually removed and cleaned the carbs.  Very little varnish was found in the carbs.  All jets were clear, the floats were fine, the diaphragms were fine, cleaned all with carb cleaner.  Same result, still dies.  I'm stumped.  A few questions that may seem foolish, but I'm grasping at straws - battery cranks fine (could it be getting weak and causing this), plugs/wires (can they be getting ittermittent), ignition controls (wouldn't they be more of an issue at higher rpm's)?  One item I've found to be a possibility is the air cutoff valves on the carbs.  Could they likely be the cause any of this?  I'm unsure what to check/do next unless this is the problem and thought other Magna owners might have come across a similar problem.  Any help would be appreciated.

[Greg Cothern]

Sounds like the slow speed jets or idle jets, most folks never pull em and they are the culprit for this exact symptom most of the time.

[86MAGNA]

Thanks for the suggestion.  When I pulled the carbs off (twice), I pulled the bowls, floats and jets out, cleaned all and cleaned the passages.  If they are causing the problem, I can't find an issue.  Since I wrote before, I also removed the 2 outside air cut-off valves (the easily accessible ones) and examined at them.  One looks fine, but the othe has an area that is either perforated or so thin you can see light through it.  I know this needs attention, I'm just wondering if these valves will cause significant idle problems?  Thanks again for all help.