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kurauzo

2004 auto-decomp Cam in 426 => Different chain size?

12 posts in this topic

Hi.

I know this may be a FAQ, but couldn't find anything exactly like this in the sticky thread about the 2004 auto-decompression cam in the YZ 426..

I bought this 2004 cam and my dealer is trying to install it. But he said that the tooth in the new cam are wider than the original one. So the 426 chain (also new) is not fitting exactly (not going all the way down) in the new, auto-decomp cam.

Then he tried to install a 2004 chain but the situation got even worse: it won't fit in the intake cam (still original) and the crankshaft sprocket..

My dealer said that installing the 426 chain with the 2004 450 auto-decompressor cam would wear both the chain and the new cam, with possibility of eating my valves/piston when the chain jumps tooth..

so what can I do now? Is it safe to use the 426 chain with the 450 auto-decomp cam? what should I take extra care?

Sorry for the big posting but this is urgent (i'm heading to the dealer tomorrow in order to check this out)...

Thanks for any thoughts,

Klaus

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I just came back from the mechanic, and said him that it's Ok with this..

I saw that the chain doesn't fit 'all the way down' in the new cam. Was somewhat afraid but I've taken the risk.

Never heard of any problems with this mod. Just hope that doesn't start with me :-(

Thanks to all

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If I remember correctly, the chain appears to ride high on the stock cams also. Again, I have a few years with a lot of hard riding on mine and all is fine. There are probably hundreds of 426s with this mod and as far I know, there are no failures accociated with it.

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If I remember correctly, the chain appears to ride high on the stock cams also. Again, I have a few years with a lot of hard riding on mine and all is fine. There are probably hundreds of 426s with this mod and as far I know, there are no failures accociated with it.

guitars,

I've compared the (same) chain fitting on both (old 'original' and new 'auto-decomp') cams, and I can tell you that the chain doesn't fit in the new cam as well as it fit in the original one.

I sure wouldn't do it if I haven't heard that this is 'normal' and there are hundreds of bikes running with it without a glitch... I'm trusting you guys :ride::applause::thumbsup:

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ok, I'll take your word on it......but don't worry, your bike will be fine....it will smooth out the hit a litte too

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FlyingGuitars lives! Man I have not seen you online in forever! Check out my two babies! :ride: (sorry for the hijack)

de71049b.jpg

And yes this one is a Yamaha (aes-720) but hey...I love Yamaha's and King's X :thumbsup:

0d3032a4.jpg

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FlyingGuitars lives! Man I have not seen you online in forever! Check out my two babies! :applause: (sorry for the hijack)

de71049b.jpg

And yes this one is a Yamaha (aes-720) but hey...I love Yamaha's and King's X :ride:

0d3032a4.jpg

Hey Satch!

I can't view pics here at work (the benefits of working for corporate america), but I have an idea of what's in the pics :thumbsup: . I'll check when I get home.......King's X is great.

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Hey Satch!

.....King's X is great.

? Are you referring to the Houston band? Actually from Missouri I think. By way of Houston.

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? Are you referring to the Houston band? Actually from Missouri I think. By way of Houston.

Yes...I think. If you're talking about the 3 piece band, that's them....the singer is a black dude who plays bass.

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