Dude I'm not riding it without an air filter, idk where everyone is getting that from, I said that I took it for a quick rip up my road the first day I got it back just to see how it ran, that's the only time I've rode it without an air filter, and it overheated while I was riding it that day without the air filter so I took it right back home, coolant was already drained and the oil was changed 5+ times with some good oil in it now, I'm not having other problems with the bike besides it overheating that time, and no it doesn't overheat while idling, but I can't even ride it at the moment since once it comes off the jumper cables it shuts right off, got the new battery today and am just about to put it in. And I wasn't riding it hard when it overheated either, maybe 35km/h thru my field then back home, and yes the cooling fan does come on.