Carbs??? Let's use some correct grammer how about throttle bodies!!
Sorry that's not the point of this response.
Let's see . . .
1. Before you take the bike to the dealer cruise works
2. Dealer takes possession of the bike does major disassembly and repairs
3. Dealer returns the bike to you with cruise and other items not functioning
I believe this is the dealer's issue!!
You cannot believe the number of times bikes developed issues after being in the hands of the dealers service staff.
But enough of this whining . . .
Cruise is made up of four sub-systems:
1. Cables with connections
2. Multitude of switches (one on the clutch, one on front brake, one on the rear brake and one associated with the throttle)
2. The setting unit on the left handle bar
3. The motorized operator under the nose cone on the left
Typically cruise mis-functions (setting and dropping) are due to switch settings however in your case it could be cable condition
or adjustments. On occasion the setting unit can go bad and I just helped a friend replace his motorized operator that failed.
Whenever I take the bike down to bare bones I always test ride to check on line routings and things like cruise control working before
I go thru the process of putting the tupperware back on. In your case since the tupperware is back on you will need to adjust the cables
by trial and error - if that is in fact your problem.
As to what direction to turn the adjusters its hard to tell. The cable set up on the newer LT's have adjusters that are easy to work with.
What year bike to you have?? The reason I ask is that the cable routings up top are different on the older bikes as BMW now sells new
cables, adjusters and a housing modification parts for the older LT's which does requires you to cut a hole on the bottom of the right hand
handle bar cover.
This pict shows a modified 2002 with the replacement kit and a hole cut out to route the new cables.
This pict shows the new routings on a new 2009
If your bike is older you may want to replace cables and resolve your adjustment issues all at one time - of course you will need to remove
the tupperware!! I believe this kit costs about $200 now and MAXBMW parts people know all the parts you need.
When I replaced mine on the 2002 I found the proper adjustment within a few turns no big issue. Why did I replace mine the cable routings
at the handle bars cause fatigue and failure casing cable breaks - this the repair ket and new routings on all the newer bikes.
Lastly as for putting the bike on the center stand and getting the rear wheel up to 35 mph in an attempt to check out the cruise that does
not sound like something I would do - accident waiting to happen!!
Good luck . . .