But I have to disagree.
Evenrude, Yamaha, Honda all have warnings on their boat motors about high speed and flags. It is a huge issue and they have a point."The issue isn't that the flags are heavy, but they provide terrific drag on the engine and the transmission, especially when the bike is at highway speeds," said Harley spokeswoman Maripat Blankenheim.
Riding at parade speeds would not likely have the same effect on the engine and transmission, according to Blankenheim.
It is also established in civil law, that a manufacturer does not have to disclaim everything, as there is no way to legislate stupidity, like the McDonald's coffee cup. If they have had many such issues, then maybe.
The guy has logged 15,000 miles on that trike with those flags flying at what have to be some great speeds - I would not hold back EVER on a bike like that! In fact I'm amazed he'd want them flying at speed....I'd want the ride.