Cam chain replacement on 04 450f

The '06 flywheel has to come off, but the stator doesn't.

The '06 uses a special flywheel puller, but not the same one as the '05 and earlier models did. Aftermarket tool companies carry them, and they are the same puller as used for a CRF450.

Thanks Grey! I wasn't sure since I haven't ever done this before.

Which years do yz450f and crf450r share the same flywheel puller?

'06-'10 YZ450F take the same puller as used on the '02-'08 CRF450.

Thanks Gray, you helped alot, but no matter how many times I tried to line up the dots. It was still out of time. I took a look at a friends bike also a 07 YZ5450f, and the intake cam seemed to be off on my bike, the Exhaust cam was spot on. I ignored the punch mark on the intake and lined up the cam lobes threw it back together and it started first kick and ran great.

My question is, because the punch marks did not line up, I was wondering if it is possible, because the cam gear is pressed on to the cam shaft, if the gear could slip and be rotated on the shaft.

How far off were the marks? It's quite common for them not to line up "perfectly", at which point you have to look at which way they are closest, or use the pin count between cams as a cross check. This is due to the fact that the marks are not precisely indexed (just aligned with the gap between two teeth), and that the chain stretches.

It is possible for the cam to slip in the sprocket, but if that can be verified, you should discard the cam or have it properly indexed and welded (costing as much as a new one, many times). In most cases, a cam that slips is the result of a seizure problem, which would mean more things to look at and attend to.

to say in your 4th to last paragraph "then check the timing" i have a 2006 yz450f how do you check the timing? is it in the service manual?

to say in your 4th to last paragraph "then check the timing" i have a 2006 yz450f how do you check the timing? is it in the service manual?
Cam timing. Ignition timing is fixed and not adjustable.

Park tools makes a nice inch pound torque wrench, small and fits in nicely! Worked great for me. Jeff

I'm changing the cam chain on my '09 YZ250F, and I noticed in the manual it says to use ThreeBond/YamaBond 1215 on "the grommet of the CDI magneto lead". Is this required when changing the cam chain?

Not normally.

Ya, its probably a stupid question...when I take the nut off the rotor (04 450), do I need a tool to counter the torque, or will it be ok to torque against whatever is keeping it from turning any further to the left?

Best choice is a flywheel holder, or use an impact wrench, preferably air.

Failing that, put the bike in 4th and have someone hold the brake. Normal right hand threads, BTW.

How do I remove the cam chain tensioner without damaging it? I do not have a manual.

Hey, David!

Are you talking about for your '06? If so, you simply loosen the bolt in the middle of the tensioner a turn or so, and remove the 2 bolts off to either side of it..... It'll pull right out then....


You don't need to unload the tensioner to remove it. Just take the inboard bolt out first, then hold it in place while you remove the outboard bolt. It's only putting it back in place that you have to wind it in.

Here's a free manual:


Maybe you can clarify something for me here....

I've wondered why my manual says to loosen that middle bolt first? :thumbsup:

Is that simply to make it easier to remove that middle bolt when you go to install the chain tensioner (when you wind in the tensioner before installing)???


It's easier to remove the center bolt that covers the unloading screw if you do it while the unit is bolted in place. It's also easier to remove the tensioner if it's locked, or unloaded (wound back) and locked, but skipping either of these steps during removal carries no real risk of damaging anything.

Question about the tensioner:

On the last ATV I had (Raptor 660) I noticed that the cam chain tensioner was basically a ratcheting design where once it had extended another "tooth" it couldn't go back. Is there a reason that these bikes do not use that design?

The YZ tensioners use what amounts to a worm gear to provide the same effect in a stepless manner.

The tensioner plunger is keyed to the tensioner case so that it can't rotate, and has has a spiral internal gear cut into it. You can think of it as a "nut". The tension screw gear is driven by the spring. The spring does not apply any real tension of it's own, but immediately takes up any available slack that appears in the chain. It can't be pushed back without the screw turning opposite the spring force any more than you can push a partly threaded bolt into a hole without turning it.

Ratchets are limited by the pitch of their teeth. Bigger stronger teeth leave more slack to develop before the next step is taken, and finer teeth are weaker and can be slipped over more easily.

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