Cam chain replacement on 04 450f

Hey guys, a friend of mine broke a cam chain last year on his 450 and it ended up costing him around $350 to fix, so I figured $13 for a cam chain is the least I can do to prevent this from happening to me. My bike is in much better condition then his, but none the less i don't want it to happen to me.

So my question is....Is it hard to change the chain out? I was thinking about tackling this myself, but i thought i would ask before I do this because i don't want to screw this thing up. I haven't really dug into my manual yet to see how big of a project this is.

Are there any tricks to this that I should know about? All i ordered was the chain. Is there anything else as far as washers or c-clips that i need?

Hope somebody can help me.

Thanks!

Note: This was written for an '04, and is accurate as is for models from '98-'05. For '06-'09 models, there is no need to unbolt the stator from anything, and the info is otherwise the same.

Takes about an hour if you don't throw in any valve adjustments.

Start and run the bike for just long enough to clear the sump of oil. Remove the cam cover, ignition cover (no significant oil will be lost), flywheel (puller required, don't cheat), and stator plate (#27 Torx bit required). Remove the tensioner (see manual for unloading instructions) and the two bolts holding the bottom of the rear chain guide shoe. Rotate the bottom end of this part outward and remove it by pulling it down. (If it gets stubborn, you can just let it sit in there out of the way.) (Note: on '06-'09 models, the rear guide shoe cannot be removed with the head on.  Unbolt it and move as far out of the way as necessary without pulling it out of the tunnel)

Remove at least one cam (both will usually be required) and rotate the chain off the crank as you did the rear guide.

In reassembling, you have a couple of options:
A ) place to the chain over the crank and bolt the rear guide back in place. Reinstall the stator and flywheel, and depend on the front and rear guides to keep the chain from looping off the bottom of the crank sprocket as they are designed to while you time and assemble the top. Probably safe, but you always find yourself wondering if the chain is really on right.

B ) Remove the spark plug and use a screwdriver to find TDC, or eyeball it by lining up the flywheel key with the bore centerline and time and assemble the chain and cams with the whole run of chain visible. Foolproof, but be sure to double check the timing by pushing the flywheel and cover on by hand and using the real marks just before torquing everything all the way up. You don't want to have to take any more apart than necessary if you screw up.

I use option b myself.

Two mistakes commonly made are failing to torque the cam caps right, and timing the cams wrong because the cams weren't rolled back. Back the engine up to a few degrees before TDC, and then roll each cam back until the front run of chain is tight, and the slack is on the back side. Now, hold pressure against the rear guide shoe by pushing your finger through the tensioner hole and rotate the engine forward back to TDC. Then check the timing. Note that there's no point in worrying too much about the timing marks lining up perfectly. The marks simply are never going to be perfect. What you do is imagine the timing marks on in the same position on the next tooth, and see how that would look. If it makes it closer, move it. If not, it's OK.

Always carefully torque up the cam caps in three successively tighter steps. I use 75 in/lb instead of 86. 86 just seems too tight to me, and I believe Yamaha has reduced that value for the later models.

It's a pretty simple job. Remember to check your valve clearances before removing the cams in case any of them need correcting, as this will be the perfect time for that.

EDIT (addendum): This procedure was originally written for the YZ450 up to '05, but applies to all other models of YZF and WRF, 250-450. Some models carry the stator plate in the ignition cover, with the flywheel inside out, and e-start models have a starter clutch to deal with. See the manual regarding the starter clutch (it's very simple). On models with the stator plate in the cover, it is not necessary to disturb it.

Thank you!!! Time to call the mechanic, ha ha

Should the rear guide be replaced ?? Does it wear well..??

How about the tensioner, should it be replaced or rebuilt ?? I plan on doing mine soon..figured Id combine it with an oil change and valve adjustment and a new plug..I would assume your instructions would apply also to a 01 426 ??

Thanx in advance for your reply....

How often should you replace the cam chain?

How often should you replace the cam chain?
once a year to every 18 months, depending on use
Should the rear guide be replaced ?? Does it wear well..??
isn't normally required

How about the tensioner, should it be replaced or rebuilt ??
check the operation of the tensioner by retracting it completely, then letting it out a little at a time. Try to force it to collapse under pressure at several positions by pushing hard against it. If it seems at all unsmooth, or skips in the least, replace it. They cannot be reconditioned
I plan on doing mine soon..figured Id combine it with an oil change and valve adjustment and a new plug..I would assume your instructions would apply also to a 01 426 ??
yes, and all other YZF's as well
How often should you replace the cam chain?

It is said every 60 hours, but I know people who run more at a risk of ruining the sprocket at the crank resulting the whole crank needing to be replaced.

Always replace the tensioner too.

Is the nut that holds the rotor on a left handed thread (turn left to tighten)?

No, it's a normal right hand thread.

once a year to every 18 months, depending on use

where does it say that interval?

definitely time to replace the 2006 cam chain! :worthy:

Takes about an hour if you don't throw in any valve adjustments.

Start and run the bike for just long enough to clear the sump of oil. Remove the cam cover, ignition cover (no significant oil will be lost), flywheel (puller required, don't cheat), and stator plate (#27 Torx bit required). Remove the tensioner (see manual for unloading instructions) and the two bolts holding the bottom of the rear chain guide shoe. Rotate the bottom end of this part outward and remove it by pulling it down. (If it gets stubborn, you can just let it sit in there out of the way.)

Remove at least one cam (probably both will be required) and rotate the chain off the crank as you did the rear guide.

In reassembling, you have a couple of options:

a) place to the chain over the crank and bolt the rear guide back in place. Reinstall the stator and flywheel, and depend on the front and rear guides to keep the chain from looping off the bottom of the crank sprocket as they are designed to while you time and assemble the top. Probably safe, but you always find yourself wondering if the chain is really on right.

:thumbsup: Remove the spark plug and use a screwdriver to find TDC, or eyeball it by lining up the flywheel key with the bore centerline and time and assemble the chain and cams with the whole run of chain visible. Foolproof, but be sure to double check the timing by pushing the flywheel and cover on by hand and using the real marks just before torquing everything all the way up. You don't want to have to take any more apart than necessary if you screw up.

I use option b myself.

Two mistakes commonly made are failing to torque the cam caps right, and timing the cams wrong because the cams weren't rolled back. Back the engine up to a few degrees before TDC, and then roll each cam back until the front run of chain is tight, and the slack is on the back side. Now, hold pressure against the rear guide shoe by pushing your finger through the tensioner hole and rotate the engine forward back to TDC. Then check the timing. Note that there's no point in worrying too much about the timing marks lining up perfectly. The marks simply are never going to be perfect. What you do is imagine the timing marks on in the same position on the next tooth, and see how that would look. If it makes it closer, move it. If not, it's OK.

Always carefully torque up the cam caps in three successively tighter steps. I use 75 in/lb instead of 86. 86 just seems too tight to me, and I believe Yamaha has reduced that value for the later models.

It's a pretty simple job. Remember to check your valve clearances before removing the cams in case any of them need correcting, as this will be the perfect time for that.

EDIT (addendum): This procedure was originally written for the YZ450 up to '05, but applies to all other models of YZF and WRF, 250-450. Some models carry the stator plate in the ignition cover, with the flywheel inside out, and e-start models have a starter clutch to deal with. See the manual regarding the starter clutch (it's very simple). On models with the stator plate in the cover, it is not necessary to disturb it.

I just adjusted the valves that were out of spec and went to assemble the cams and torqued them to spec by starting at the 30 inch pounds then 45 and finally 75 in/lbs and the step from 45 to 75 my torque wrench didn't tighten the bolt it clicked right away. It should have moved the bolt a little tighter and then clicked but it didn't. What is your opinion. I am trying to find another torque wrench to verify the first but am coming up short.

I just adjusted the valves that were out of spec and went to assemble the cams and torqued them to spec by starting at the 30 inch pounds then 45 and finally 75 in/lbs and the step from 45 to 75 my torque wrench didn't tighten the bolt it clicked right away. It should have moved the bolt a little tighter and then clicked but it didn't. What is your opinion.
Your torque wrench is untrustworthy, or you made a mistake.

Back the bolts off and start over, see if the same thing happens again. If anything like that happens the second time, have your wrench tested.

I thought I made a mistake so I tried it again and the same thing happened. I will get a new torque wrench to get it right. This is such a critical step that I want to make sure it is correct. Any recommendations on a good reliable torque wrench that won't break the bank?

Not really. I've been trying to find a flex beam 1/4" wrench with the right range that I can recommend, but they're hard to find anymore. You can go with harbor Freight and get something really cheap (and you know what they say), or step up a little to Craftsman, etc.

NAPA Auto Parts has a tool line that's not bad (Balkamp). Try browsing their site.

I thought I made a mistake so I tried it again and the same thing happened. I will get a new torque wrench to get it right. This is such a critical step that I want to make sure it is correct. Any recommendations on a good reliable torque wrench that won't break the bank?

Couple years ago I purchased a Napa (kc tools brand I think) 1/4 drive inch pound one for about $120. I sent it out after using it for some time to some company back East somewhere to calibrate it for about $40. I've had good luck with it.

I have the craftsman torque wrench but as you noted in the previous post it seems a little untrustworthy. Gray are you referring to the beam flex instead of the twist adjustment? I have seen both and thought that the beam flex wasn't as accurate as the digital or the twist selector. I will check out the napa site and see what they have available.

BTW, I have a 1/2" drive clickable t.w. that has a broken handle (locking mechanism) and was told that Craftsman does not provide lifetime warranties with them only wrenches????? This was a t.w. that was only used for torquing the lug nuts on my rv 6 times a year. Also, be sure that you're holding the wrench properly. Don't over torque it by holding the wrench with one hand on the socket and one on the handle. Only the handle unless you need to guide it.

Thank you!!! Time to call the mechanic, ha ha

i called 2 stores in my city and they want $200-300 for labor:bonk:, just to change a cheap timing chain. 2-5 hours as they call it.

guess ill need to learn how to do that as well.

any good video links will be very appreciated.

i already read all the tt ones word by word, but video always make is alot easyer for me.

do i need a new gasket for the outer engine cover or just for the tensioner?

SureBlue sed its a most to use a new timing chain tensioner, whats your opinion ?

GT

'05 or earlier, the tensioners are very robust. They're a bit less so in the '06 and up models. You should replace it if you have any doubts.

I plan to replace the timing chain with a new topend in the near future and wanted to clarify that on the 06 450 the flywheel will need to come off to do this.?? Is this the case. If so is the only puller to use the OEM Yamaha one, or has someone used another one successfully??

Any help would be greatly appreciated.

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