>I've tested my idler stabilizer valve on my 87 Westy and it has continuity,
>yet it does not buzz. Checking the book, states that you should check the
>ISCU. Well that's fine, but where is it? Can it go bad? 
>
>
The first time I tried to find my ISCU (Idle stabilizer), before I had a
Bentley's, I didn't find it. It's located in front of the right tail light.
I haven't tried it but it might be possible to reach it by removing the tail
light assembly, I wouldn't recommend this approach. The better, correct?,
way is to remove the plastic panel just to the right of the air cleaner. It
is retained by four small metal clips. They can removed without damage by
using a small 90 degree pin tool/awl to gently lift the two retaining tabs
of each clip. IMPORTANT.. remove the right air intake grille, the black
thing covering the ait intake <g>. There is a paper/plastic/tin foil hose
attached to both the plastic panel you are trying to remove and a ,for lack
of a better word, snorkle. You need to loosen the snorkle from its rubber
mounts so that it and the hose can be lower as the plastic panel is removed.
IMPORTANT.. failure to do this will most certainly damage the intake hose
and lead to a very difficult to find power loss, been there-done that.

Now you can see the ISCU, hooray. Check the sockets/pins for
corrosion/looseness. If all looks OK put some dilectric paste on the
contacts, reinsert and hope for the best.. In a shop situation if the
obvious tests are OK and it looks good I would install a know good unit for
testing ie: do you have a friend with a similiar setup?

Good luck and while you have the panel out it would be a good time to treat
the body seams to prevent/stop any rust.