Help! timing chain or cam noise

I just adjusted the valves on my son's 04 450. It ran fine for about 5 hours and today he brought it home and said it had aweird engine noise like my 03 only louder. I thought maybe i forgot to tighten something during valve adjustment or something had worked loose. Timing appears dead on. while pushing the kickstarter i noticed that the cam and chain seem to jerk. At first i thought it was just due to the roller on the far right of the decomp lever rolling over the pin on the end of the camshaft but it also does it again approximately 180 degrees later. I've searched the forum and didn't see this problem in the search. any help would be greatly appreciated. Thanks Ed

Is the tensioner at it's max and have you replaced a cam chain.

We haven't had the bike very long but i haven't changed the cam chain. I honestly don't know if the tensioner is maxed out or how to tell if it is. When i adjusted the valves the tensioner moved in and out all the way freely. Later today I'll see if the tensioner off my 03 will fit and see if that makes any difference. Ed

Is the tensioner at it's max and have you replaced a cam chain.

The tensioner was not at max in fact it was only 1/3 to 1/2 extended. Now here is where I got very lucky. My son said it started to get a little louder than normal and he shut it off immediately. Thanks to your advice i checked the tensioner and found that the spring on it had broken (the pieces were still in the tensioner). I swapped the tensioner off my 03, started it up and it ran great, not hard to start, no backfiring or any other unusual noise. I'd say the odds of getting that lucky again with a tensioner failure are probably very slim. Thanks for the reply it saved me a lot of headaches. Now if my luck will only hold out and the dealer will have one in stock sowe can go riding tommorrow. Thanks, Ed

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