I almost found this by accident, when trying to cut across from AR-7 to AR-123. It's a short road (7 miles), but a long downhill as it's downhill the entire length of the route. Going east-to-west, that v-twin is getting it's workout most of the way up. Going west-to-east, you can't really ride it fast as you'll pick up too much speed. Basically a mix of coasting and riding the engine braking most of the way.
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