Motorcycle Repair: Honda Shadow 500VTC high idle, gas bike, air leak

Question
1983 Honda Shadow 500 VTC

Hi Mark

Here's what I do know:
Carburator has been cleaned, new spark plugs...old ones were very black, air filer is clean, have had oil/filter changed, fresh gas.  Bike starts good and idles good when cold.  After riding a bit and then I have to stop, the bike will drop rpms until it stalls.   Will start up again but will continue to stall unless I'm consistenly on the throttle (again this is when I'm stopped).  If I've been driving for a long time (about an hour) and then come to a stop, the idle will stay high (around 3000) unless I shut the bike off - I don't even have to let it cool, however; Once I get going again, next time I stop I will have the same problem.  Once in second gear and all the rest the RPM's seem to be fine however it does seem to run a bit rich and there's lots of black exhaust when this is happening.

The idle adjuster has been played with endlessly with no end to the problem.

Any suggestions you have will be appreciated.

Thank you
Sincerely, Debbie

Answer
Hi Debbie,

I suspect the carbs are varnished again and/or not thoroughly cleaned.

Your problem description is consistant with: obstructed pilot jets/circuits, an intake air leak, and un-synchronized carburetors.

I'll need an email adress as requested to return repair info files. My email addy is:  mshively1@woh.rr.com

Respectfully,
Mark Shively