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SincYZ450f

Timing Chain 2004 YZ450

10 posts in this topic

Just wunderin if any1 has ever had problems with there timing chain? How often do u replace it if at all??

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Yes, they have.

If the chain wears too much, it "stretches". Actually, the plates don't really stretch in the elastic sense much at all, but the wear that occurs at each pin and plate joint cumulatively makes the chain a longer pitch (the distance between links) than it should be.

This will lead to two things, both bad. First, a worn chain will accelerate the wear on the crank sprocket. This is a bigger issue with the YZF's because the sprocket is cut directly on the crank, and when it gets worn out, the crank has to be replaced in order to fix it.

The other thing is that the chain may get long enough and/or fit the sprockets poorly enough that it will jump time, usually at the crank, which can bring about the general demolition of the entire top end, if not more.

Considering it's a $25 job that takes 1 1/2 hours to do, it's well worth doing periodically.

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It says in the manual to replace the cam sprockets and chain as a set.. is this completely necessary? I went ahead and got the hotcams anyway.. my poor wallet

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As a rule of thumb I replace the both the timing chain and Auto CamChain Adjuster when I do a top end. Both of these parts are 20bucks or less and both are prone to failure over time. To me it is cheap insurance. A no brainer :)

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As a rule of thumb I replace the both the timing chain and Auto CamChain Adjuster when I do a top end. Both of these parts are 20bucks or less and both are prone to failure over time. To me it is cheap insurance. A no brainer :)
I'd love to buy a tensioner for that. Retail is $50, $15 for the chain.

The cam sprockets won't wear very rapidly, and don't need to be replaced with the chain as a rule. I also have yet to see a faulty YZF tensioner. If someone has one, I'd like to see it. I don't generally replace them except on very high-hour engines

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I'd love to buy a tensioner for that. Retail is $50, $15 for the chain.

If someone has one, I'd like to see it. I don't generally replace them except on very high-hour engines

I have my tensioner off my bike right now (#5 http://oem.thumpertalk.com/2004YZ450Fcamshaft.aspx) and can't seem to make it retrack or move in any direction in or out? If i understand it correctly, this tensioner is suppose to move in and out while turning it's bolt in or out to put resistance on the chain damper right? If so, why can't I get it to move? I even put it in a vise and gently closed the vise to apply some pressure on it expecting the tensioner to compress but it didn't? Any suggestions?

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I have my tensioner off my bike right now (#5 http://oem.thumpertalk.com/2004YZ450Fcamshaft.aspx) and can't seem to make it retrack or move in any direction in or out? If i understand it correctly, this tensioner is suppose to move in and out while turning it's bolt in or out to put resistance on the chain damper right? If so, why can't I get it to move? I even put it in a vise and gently closed the vise to apply some pressure on it expecting the tensioner to compress but it didn't? Any suggestions?

yes buy a new one.......or reassemble and be worried all the time that a failure is just around the corner....possibly a very expensive alternative

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The bolt on the rear end of the tensioner is a plug. Remove it completely, then insert a small screwdriver to turn the spindle of the tensioner.

Turning it against the spring tension retracts the plunger. When you release it, it will spring forward, and you should absolutely not be able to push it back simply by pushing against it. When completely retracted, it should stay retracted until you turn the screwdriver slightly in the direction of spring pressure to release it.

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