Well Fred, I've been searching for some nice, angled, motorcycle valve stems for some time now and here's what I found.
The 90 degree jobs may have some safety issues if you don't support the stem. They are mostly intended for cruiser riders who rarely run hours or days at a time and at nowhere the speeds the LT is capable of. Even my friendly Honda parts guy would not recommend using the stems that come on the Gold Wing.
The really nice valve stems ( low profile metal with ~45 degree heads) that come on Ducatis and Triumphs at my local dealer (BMW North Dallas) WILL NOT FIT any stock LT wheel. They are available on the net in either 8mm or 10mm sizes mostly via sportbike sites. Guess what? Measured a valve stem I saved after my last tire change: 12mm on the LT stem! The BMW service manager is just as frustrated as I am that these are not available in the correct size for the LT.
So, that leaves me, and maybe you, wishing and hoping for some enterprising sole to make these parts available. If you find some, please post where the heck you can get them!
Get busy livin' or get busy dyin'!
2003 BMW K1200LTC "El Gato Grande"
1993 Suzuki GSXR1100W
1978 Suzuki GS1000C 'Project'