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Hey guys- I'm in the midle of a valve adjustment on an 05 yz450. I'm having a hell of a time getiing the chain back on the sprockets.Just can't seem to get it over both at the same time. Yes the tensioner is removed. I must be an idiot or something but is there a specific way to do it? PLEASE HELP!!!!!!! Jason

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It should be difficult to do, since the engine is designed to help you avoid it, but you may have "looped" the timing chain. This condition is when the chain skips a tooth on one side of the crank sprocket, but not the other, as the chain runs around the sprocket in a sort of "U". This leaves one pin of the chain hanging off at the bottom and makes the whole thing that much shorter. In a way, that's good, because you would not want to assemble it that way; your cams would jump time as the link was picked up later. The problem is usually caused by rotating the engine with the cams out without pulling tension on the chain.

Unfortunately, the only way I know of to verify this is to pull the ignition cover and flywheel to get a clear look at the bottom of the crank sprocket. If it needs to be corrected, you'll likely also have to remove the stator and free the end of the tensioner shoe to get enough room to run it back onto the sprocket correctly.

Good Luck. :)

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Hey guys- I'm in the midle of a valve adjustment on an 05 yz450. I'm having a hell of a time getiing the chain back on the sprockets.Just can't seem to get it over both at the same time. Yes the tensioner is removed. I must be an idiot or something but is there a specific way to do it? PLEASE HELP!!!!!!! Jason

Same thing happened to me last weekend. I'm not sure if you can take the slack out without removing the front chain slipper, which means removing the head. Maybe if you pop the flywheel you can, I took the head off.

Here's a clip from a WR post from last week. -

I get the head on and torqued and then hit my second problem when I try to pop in the cams, the cam chain is too short.

It slipped a tooth on the crank sprocket and there is no way to tighten up the hanging link with both cam chain guides in place so I had to remove the head to remove the chain guide, set the cam chain properly on the bottom sprocket and bolt everything back together again.

The correct measurement for a properly seated cam chain is 7 ¾ inches measured from the top of the cylinder to the top of the cam chain if you’re holding it up at one point, like by a zip ty. If your measurement is less than that there’s a link hanging under the crank sprocket.

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Same thing happened to me last weekend. I'm not sure if you can take the slack out without removing the front chain slipper, which means removing the head.
Removing the head is NOT necessary to correct a looped chain. But as I said earlier, removing the flywheel and stator usually is. Once these are off, the bottom end of the tensioner shoe, not the guide in front, can be unbolted and moved clear of the sprocket so that the chain can be put in its proper place.

Removing the head is only required if the front chain guide is mispositioned during the installation of the head. (and please never ask me how I know that.) :)

:)

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Removing the head is NOT necessary to correct a looped chain. But as I said earlier, removing the flywheel and stator usually is. Once these are off, the bottom end of the tensioner shoe, not the guide in front, can be unbolted and moved clear of the sprocket so that the chain can be put in its proper place.

Removing the head is only required if the front chain guide is mispositioned during the installation of the head. (and please never ask me how I know that.) :)

:)

It was easier for me to pop the head off since I had just torqued it on a minute earlier, and I didn't have a flywheel puller. I popped the head, removed the front guide and just wiggled the chain to free the loose link. It would be much simpler to fix it as you suggested but I wasn't sure if it could be done and I wouldn't want to give out bad advice. Thanks for the tip. :p

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Thanks Cowboy- Took me almost a half hour to find you correct post on the other site. But once I found it the light bulb went off..... Thank you so much. You're right, once you know the secret it'sa piece o' cake. Thanks again, Jason

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I didn't have a flywheel puller.
Dude, they're like $10 and they YZ one fits nearly everything from Japan. You gotta have one. Besides, then you can play the hero one day when one of your buds needs one.

:)

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Dude, they're like $10 and they YZ one fits nearly everything from Japan. You gotta have one. Besides, then you can play the hero one day when one of your buds needs one.

:)

Oh and when you do get one, make sure to take the nut off the fly wheel. Before attempting to take the flywhel off! :):p

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Dude, they're like $10 and they YZ one fits nearly everything from Japan. You gotta have one. Besides, then you can play the hero one day when one of your buds needs one.

:)

Dude, 2 things, - 1 - nothing is 10 bucks up here, a jug of OJ is $12 if you can get it, and 2 - there are no bikers here to ride with so I'm nobody's hero. :D That's why I need TT, some bikers to talk to to keep me sane.

You gotta realize where I live. :p

I'm 100 miles from the Arctic Circle, I can't just run to the corner and buy one. I have to order and fly up everything I need and it usually takes a month. Luckily I did find a 3 arm puller in town that fit after some grinding so I'll be ready for next time. Before that it was tension on the flywheel with tire irons and a smack on the nut with a ballpeen hammer. Crude but effective. :)

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Frosty man.... You need to move south in a big way. One of these days you are going to completly loose your mind up there.

I guess that's a good sign....that you think I still have a mind to lose. :)

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