I recently had a radiator cap fail and cause me to go crazy for a bit, simply because I wanted to finally do some maintenance on a perfectly running bike. My 2006 R1 has 16k miles on it. Virtually everything on it is untouched except for oil and filter, and even that I accidentally neglected for 6 years/9k miles. Recently upgraded it to commute duty, so I've been trying to take better care of it. The bike was running perfectly. But I wanted to flush the radiator. So I did. I even burped/bled the system as recommended online. All was well. Put the cap back on and rested easy. Except, the next day it pushed some fluid out of the overflow when I got to work. I figured it was no big deal, just overfilled something maybe. On the ride back home, it actually lost fluid out the overflow sitting a stop light. Not good. I got home and removed some water from the overflow to make it sit at the max level line. The next day, on the way to work, the bike reached 235 degrees in traffic, something I had never seen. I took it apart before leaving for home, and refilled the radiator with distilled water. It took about a quart of water. Burped it again. Extra burping. Put cap back on. Bike ran cool now with the proper fluid, but I noticed even coming to a stop at just 190-200 degrees, it was already moving more fluid into the overflow tank. I figured it had to be the cap. I stopped at the dealership. Got a new cap for $30. Put it on. All problems solved. That cap must have been on its way out, but was holding on somehow since it hadn't moved in 13 years. Once I removed it, it never sealed the same again and wasn't able to hold pressure. It was sending fluid into the overflow WAY too early, and it doesn't even seem like it was sucking it back in either. Just made me realize that even when doing regular maintenance before a big trip, its important to leave a few miles to test everything you did, because sometimes there are unintended consequences.