HEy I am going to be tearing down my 2003 yz450 to install a new crankshaft(timing teeth are badly worn), ive been doing alot of research and it seems you guys and girls know your 4-strokes. Id like to give something back and post up digtal pictures of the complete job so it will make the next guys job easier. Im hoping you guys will give me your support for this is my first time tearing apart the bottomend. the status now is the engine is out of the bike, the cylinder head and cylinder are off the engine. Well this is what happened, I was riding at this local sandtrack and i was hitting this stepup that a 125 was clearing with no problem while my bike was struggling, the bike then was hard start, it took like 40 kicks, it started up fine though and so I did a few more laps and was beating the bike and all of a sudden it starts running like my xr100, no power, and sounds like an silenced king quad so i kill it and wait for my buddy to let him know im out of there, the 450 doesnt start, i was kicking the piss out of it, after about 200 kicks it starts(note that im a mile away from my truck on someone elses land so pushing it back wasnt an option) ,so i make it back and take it home, i com to find out-- ---the timing has jumped off and so I adjust it, the chain was a little loose but i figure i could start it, so it starts perfect, i go to start it again and it wont turn over the timing has jumeped again, the camshafts are worn and the chain is stretched along with the cranshaft timing gear being spent and the front cam chain guide is eaten up, I ordered new cams, chain ,guide and crankshaft, should i get a new tensioner? it seems like the old one works just fine, also should i just replace the other timing chain guide? it doesnt seem to worn out. also has anyone bent a valve doing this?how would i check that?