I just finished with a twenty thousand mile service. Break fluid, coolant, oil and rear end, plugs, air filter cleaning. Getting her ready for the spring season. Plugs and coils came out clean no rust, not even dirty. The bike is used, not a garage queen. Lots of dirt miles there. I did have a 2012 that had same rust on the plugs the few times they where changed. Not sure if yamaha changed anything or what, but they did look to be the same. Just 2 cents