In the first scene, while Ponch (Erik Estrada) and Jon are talking and riding side by side, part of the decal on the front of Ponch's helmet is missing. At the end of the first chase, the decal is back to normal.
In the first shot of John and Ponch on their bikes, it is obvious that John and Ponch are sitting on motorcycles that are being towed on a trailer, as John pulls in the clutch lever, for no apparent reason, and holds it in for 6-8 seconds, yet the two motorcycles stay perfectly side by side. With the clutch in, John's motorcycle should have started slowing, and John should have started to fall behind Ponch a little.