Back in august, I mentioned using a Carbtune to sync the throttles on My 2000 LT in this thread
Post # 12.
There's info about throttle sync in the Hall Of Wisdom, and I'm sure there's more buried in the LT forum somewhere.
So.... I thought that I would add a little more info about it.
It's not mentioned in the BMW maint. schedule, and I guess it's not supposed to be required.
.... after reading a review of the Carbtune in a motorcycle magazine (Rider Maybe), I ordered one & gave it a try.
If You've ever used a mercury manometer, You know how crappy they are!
The effect the T-sync had on My LT was to smooth out the vibration around 4,800 rpm (a little) and steady the rpm at idle.
And it was fun! (sort of). You may also get better throttle response.
Here's the website
Morgan Carbtune - carburetor synchronizer for balancing motorcycle carbs
I think that your best deal is to order directly from the Mfr. $88 + about $12 for shipping.
You can also get them on Amazon.
Note: If you're going to do this job, and you're not the mechanically inclined type....... enlist the help of someone who is. (just say'n)