Producers used the same trailer for filming in season 3 as they did in the first two seasons. The bikes on the trailer were still KZ-900. Because the difference would be visible, they removed the KZ900 windscreen and put a KZ1000C1 windscreen on the bikes but they forgot to replace the pursuit lights (they are bigger on the KZ900) and the metal frame below the headlight (missing on the KZ900).
In mid '70s CHP tested other motorcylces such as Moto Guzzi Eldorado, Honda 750 four and Suzuki 850 (this last one can be seen in the background at Central parking lot in many episodes of the second season), all those motors looked really similar because of the Department specifics such as saddle bags, radio box and pursuit lights so it is not easy to spot the differences.
Erik Estrada owns one of the KZ-1000C1 used in the series.