Motorcycle Repair: honda gw 1200 will not idle rough, emission control devices, air suction

Question
Hi Bill. i bought 1986 interstate gold wing 1200 6 monts ago idleing was bad.i took it to a shop they clean the carbs and check it out but could not fix it. it starts good then it will not idle then there a loud rattling or clunking sound comming from the eng.open the trottle the noise goes away and it ride like the wind close the trottle and the idleing is that bad it shuts of i need help THanks...e pope

Answer
Elmo, did they check the air cut diaphragm on the air cleaner box? Normally they are mounted on the carburetors themselves, but the illustration at the PARTSFISH website, seems to show the diaphragm on the air box itself.

There are several emission control devices on the engine.... purge control valve and air suction valves for the pulse air system. Many of these devices are regulated by a vacuum signal from the intake manifold or carburetor ports.

The rattling engine sound is probably the primary chain flipping around. This happens when the engine is not running in a balanced condition... any irregularities with the compression, ignition timing and carburetor balance will cause this type of noise. Get the cylinders balanced properly and the noise should subside, unless the bike has a LOT of miles on it.

Check with the http://www.gwrra.org/ site for more assistance. Wings are really not my "thing" as a vintage bike.

Bill Silver