I have had a lot of good luck with food motivated horses. I hire my friends' teenage boy to ride his undersized bicycle near the paddock or pen of the horse i want to teach about bikes. At first I have him keep quite a distance, then gradually cut down on the size of the comfort zone. We have the rider put horse treats in his pocket, and park near the pen & quietly offer them to the horse. After a few
moments, the horses will start to estimate where he will park & meet him there for the treat. After a few more tries the bicyclist can pretend to wipe out, drop the bike, etc. It's great fun for the kid, and safer than me riding the dang bike. I think it's important to have the bike do lots of things. I have seen horses used to bikes freak out if the rider goes off, so better to expose them to that too ! Piggy horses will eventually learn that dealing with something weird can earn you special treats !
