Just want to say how awesome I think this forum is. I just joined up, but have lurked for a while since picking up a 03' yz450f. Looking for a little advise, hopefully someone can chime in. I just picked this bike up, and have honestly, very little info on its history. I'm pretty sure however that the cam chain is in need of replacing. It seems to be quite noisy when running, but I have very little to compare the noise level to. I have several issues with that though. 1. I come from sportbikes, just getting back into dirt after years away, and every sportbike I've torn down in the past, the cam chains are pretty much taught, there is no slack to speak of with a proper tensioner in place, and tolerances are usually pretty tight. I'm assuming this is correct for this machine as well? 2. I bought this bike as a SM with a baja designs kit, also all the dirt goodies. My main problem with the kit so far is that the left crankcase cover is replaced with the baja designs stator and cover and does not allow for you to use the crankcase window to line up the timing marks per the service manual. I have put the bike to what I believe is TDC via a rod in the plug vacancy, and the cams seem to be in correct time, but I'm not sure that this is sufficient to measure TDC.....I really wish I had the crank/flywheel marks available. Opinions? 3.With what I believe to be TDC, there is quite a bit of play in the cam chain between the cams. I can easily grab it and move it up and down for a full range of about 1/8" to 1/4". I believe this to be out of spec, but could not find a source that gives any hard number for measurement. 4. I also have been unable to find a proper way to test the tensioner. At this point, I'm assuming replacing the chain is a cheap and realistic thing to do, and then the tensioner if there still seems to be slack post new chain installation. If anyone has any advise, or could give me a little confidence that I'm at least on the right track here, it'd be greatly appreciated. I just don't want to go around replacing parts just because. Thanks.