We have a 2005 Rubicon with 7400 miles and it making a rattling noise coming from the engine. We had a dealer look at it and he said it sounds like the crankshaft. He did not tear it apart, he was just going by the way it sounded. Made a topic on this a while back.

We had someone else listen to it that works on vehicle and tractor engines full time and he said it sounds like the timing chain(also known as cam chain?) I believe it has a self tightening chain. Also, sometimes when I shut it off, you can really here it then. Is there a way to know for sure that it is the timing chain without having to tear it down? How big of a job is it to replace the timing chain? How long do timing chains tend to last? To me, this seems kind of early for a timing chain. On vehicles they last 100,000 miles or so. I know atv's and vehicles are totally different but still.

Now it has a cam chain tensioner and a tensioner lifter. Is the tensioner lifter what keeps the cam chain tight? If so, is it possible that the lifter just needs to be replaced? Do they go bad?

If it is actually the timing chain, I need to get it fixed as quickly as possible. Man, if the timing chain comes off, the fourwheeler will really be messed up.

If it would help, I could try to post a video of it on here. Is it possible to post videos on here?

 

The cam chain tensioner is on the left side of the cylinder (when sitting on the bike) just under the exhaust header pipe .. If the engine has been run long with a bad tensioner then the cam chain could be stretched and the tensioner may not adjust it enough ..

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I did not realize you could tighten the chain manually, good to know. I will give that a try.

Does it tell you how to tighten the chain manually in the service manual? I did not see that anywhere.

 

You can't actually tighten the cam chain this way because if the tensioner is faulty it will slip back , this is a way of checking both the tensioner and chain .. If it does quiet the engine down when you turn the tensioner screw then I would replace the tensioner as soon as possible ..

 

What do I have to take apart to get to the tensioner lifter? Would I be able to start the engine while I turn the lifter?

Thanks for the help, HondaMechanic