I used to notice on my WR450 that it would make a little thud/clank (I don't know how best to describe it) when I would land hard. I chalked it up as probably the kickstand and didn't think much of it. Then I just got a new YZ450 and it makes a similar noise. Maybe it's the chain but it doesn't sound like chain slap (do chains make a unique sound when you land hard). The chain is adjusted correctly. It's hard to describe but it's what I'd imagine the sound would be if the motor mounts were slightly loose and aluminum on aluminum clanked a few mm when you hit really hard. I think I've checked the torque on every bolt on my bike and everything is correct. Is it the sound of alumimum flexing somehow? My WR is steel framed but I have no way of knowing if the sound is the same or something else. I also have a GYTR skid plate on my YZ but it's cranked down tight and my WR doesn't have one on it. Do I just ignore the sound or is something wrong. I'm a fairly new rider so it's messing with my mind. I'll go through a rythmn section of 3 doubles back to back and start thinking, what's that sound off the first double then I land and while in the air over the second doubles my mind says man is my front wheel/axle loose 'cuz it just felt weird, then I land after the 3rd set of doubles and all is well. It's probably nothing but better safe then sorry.