My bike (99 yz400) has always had a ticking noise and didn't think much of it until I rode an 04 WR450 that didn't make the same noise. It doesn't make the noise when first started, but it does as it warms up. Here's what I know: 1) The valves are in spec, I did them myself. 2) The cam chain and tensioner are stock, I haven't replaced them yet. I'm going to soon. 3) The motor is all stock, never been taken apart. It doesn't have a ton of miles on it, I'd guess I probably put on less than 20 hours a year. 4) I have a skid plate, but I don't think it's the skid plate amplifying the noise. 5) The noise is present at idle, in gear, going or stopped. 6) I thought it was an exhaust leak, but sealing the header and junction to the muffler didn't help. Anybody have the same light ticking noise and actually solved the problem? Thanks!