Motorcycle Repair: VOES, emissions testing, vacuum switch

Question
QUESTION: Hi Mike,  My 1993 FXDL drops it's idle speed ~300 RPM, on restart, after it's gotten hot idling then turned off. Either letting it sit to cool or riding it causes it to revert to the set idle speed.  Reading the repair manual I see the VOES could do exactly that so I'm suspicious of it.  But, I don't understand how a vacuum switch could be affected by heat that way.  Ideas?  Thanks,

ANSWER: Are you saying the idle speeds drops after warm up and then the bike shuts off? What is the before and after idle speed?
Mike

---------- FOLLOW-UP ----------

QUESTION: Bike drops from 1300 to 950 after idling in 100+ temps for ~10 minutes outside the emissions testing station, but does not shut off by itself.  Turned off for ~5 minutes while testing personnel attach their devices, ready their computers, etc, restarted for test it still idles @950 & fails emissions.  Rode it home and upon arrival it again idled at 1300.  1300 historically is required to pass emissions testing since it won't at lower speeds.  Recreated the entire scenario in my garage to verify it wasn't a one-time thing.
Seems heat related to me and I'd suspect the module but read about the VOES and thought I'd ask your opinion.  Thanks.

Answer
What the VOES does is advance the timing after the bike is running. You can chaeck it by starting the bike and unpluging the hose and putting your finger on the hose. When you unplug the RPMs should drop. When you plug it back in they should go up a little.
Moduals susally dont fail like that. The pickup might be failing, but ususally they totally fail when they get to hot and the bike shuts off. Then when it cools down, the bike wills start
Good luck and happy riding
Mike