It's been my experience that sometimes my basenji just gets it in her head that she doesn't like another dog, and for seemingly no good reason. I have been able to mitigate her behavior, but this is not a cure….
First, an excited basenji is a biting basenji. Make sure he's calm. Make him sit. Exert your dominance. Stand over your dog, look him in the eye. You need to snap him out of his mindset and remind him that you're in charge and he doesn't need to be aggressive.
It will take time and patience, but he can be made more comfortable...
I've also found that walking together as a "pack" helps. The two humans in the middle, the dogs held on a very short leash to either side, and you ignore your dog's aggression, focusing them on the walk itself. After a short while, they should just about forget one another. But this also acclimates them to each other. Good luck!
