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Michael Cahill

Cam Cahin Tensioner Question??

14 posts in this topic

I know this may be a repeated topic, but i think mine is kind of unique.

I recently was looking over my bike, and noticed that the little "cap bolt" that goes into the end of the cam chain tensioner is broken off at the head.

Is this a bad thing that i cant get into the tensioner to tighten it back up if i ever take it off?

because im planning on checking all the valves, and pulling out the chain to check it.

So basicly, will i be able to retighten the tensioner if i take it off?

Thanks, Michael :confused:

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The trouble will be that you won't be able to slack off your tensioner to re-install it. The tensioner is designed to take up any slack that may appear, and it will not back off unless the center tensioner shaft is rotated back with a screwdriver.

This is not the end of the world, however. Once you get the tensioner out, a competent technician (like you, maybe even) can remove the broken bolt. It's an ordinary ISO metric cap screw, so it can be replaced with almost anything.

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So your saying i should just be able to drill and tap the screw and screw it out?

So the screw is just simply a cover then? it is'nt holding the whole thing toghther?

that's what i was worried about.

and while were on this toppic, is the cam chain itself something that requiers replacement often?

because its a 98 bike, i'm the 3rd owner, and i dont know if at all, or how many times its been pulled out and replaced.

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So your saying should i just be able to drill and tap the screw and screw it out?

So the screw is just simply a cover then? it is'nt holding the whole thing toghther?

that's what i was worried about.

and while were on this toppic, is the cam chain itself something that requiers replacement often?

because its a 98 bike, i'm the 3rd owner, and i dont know if at all, or how many times its been pulled out and replaced.

The bolt holds nothing together. It is basicly a cover. You should be able to use a drill and easy out no problem. I would definitely replace the cam chain. They are only 15 dollars or something.

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ok thats what i thought just wanted to make sure!

Now to remove the cam chain will that take a mass ammount of dissasembly of the lower end of the motor?

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Now to remove the cam chain will that take a mass ammount of dissasembly of the lower end of the motor?

Changing the cam chain only takes an hour (maybe 2 hours the first time). You need to pull the shifter off, mag cover, flywheel, and stator on the lower end. On the top side you need to remove the top engine mount, valve cover and both cams (remove the tensioner too).

The cam chain should be replaced every year (if you ride 2-3 times a month).

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Cam chains are pretty simple stuff:

http://www.thumpertalk.com/forum/showthread.php?p=3150405#post3150405

But the chain for a 400 or 426 is more like $30. YZF tensioners are such simple, effective things that if it seems smooth, it's probably still OK. But it is 10 years old, and it wouldn't hurt to replace it.

The broken bolt will probably spin right out of place if you can use a reversible drill and a left handed bit.

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oh ok, now is there any way to tell if it needs replacing or not?

and this is a stupid question i know, but i take it i will need a flwheel puller?

or is there another way to take it off?

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You will need a flywheel puller, yes. One of your friends with any other kind of YZ, or most other recent Japanese two-strokes may already have one that works. Don't attempt to use something else.

Determining whether the tensioner needs to be replaced can be somewhat imprecise. If you retract the spring, then push the plunger against something solid, you should be able to let the plunger extend a little, then push against it and not under any circumstance, at any point in its travel, have it slip back in, or even feel like it might. The plunger must extend and retract smoothly throughout its range. If it will pass these checks, it may very well be fine. If it won't, it certainly is not.

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Oh ok,

Well that makes sense, but what i really wanted to know is,

Is there a way to determine if the cam chain needs replacing, without taking it all the way out?

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