This fell off my '78 R100/7...

[0m3nc0w]

Changing out the handlebars and this fell out from INSIDE the handlebars once I got the LEFT grip off, throttle and right grip were still attached... Does anyone have any idea what it is? I'm new to old airheads

Obviously it is small (dime size) as it fits in the bar lengthwise.

[john5t]

Looks like the handlebar perch wedge:
http://www.w6rec.com/duane/bmw/perch/index.htm

[Texer]

Kind of a bonus that turned up. Sometimes they're missing.

[Airbear]

Wow, you've got a real one! I've had to carve mine out of hardwood.

[montmil]

The pinch bolt/screw for the perch captures that danged pricey wedge. Most new-to-Airhead owners lose this item and may eventually crack the perch casting. Mother Magura eventually altered the design of the perch which eliminated he need for giving yourself a wedgie... As I discovered when I purchased a used perch off fleaBay. Bought my wedges from Hucky.