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spc mike

quick question about 450 cam swap??

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can i use a 450 cam out of an 06' yz450f in my 02' 426 to get the auto decomp feature? i would love any help!:banghead:

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I am not 100% sure, but I don't think so. I know that 03-05 450 ad cams will work. I belive that 06 and up will not.

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The cam will fit, and I see no reason why it won't work, although I know of no one who has used that cam in a 426 for this mod. The question would be as to what the power delivery would be like. The '03-'05 cam (5TA-12180-00-00) is widely used, and produces a wide, smooth power curve that eliminates the spike, or "hit" that the 426 has at around 5000 by coming on harder sooner, and in a more linear fashion. The '06 cam (5TA-12180-10-00) has slightly different timing, and has a little more bias to top end power. It could very well work out quite nicely in the 426, but as I say, I know of no one who has used that particular cam, so I couldn't say for certain.

The '03-'05 cam will do exactly what you want, however, and is one of the best mods you can do to a 400/426. When you get ready, read these:

http://www.thumpertalk.com/forum/showthread.php?p=3706078#post3706078

http://www.thumpertalk.com/forum/showthread.php?p=5378040#post5378040

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that you very much for i the information! i think will try the 06 cam just to ob one of the first ones to try it and because i can get them for pretty cheap.

But also can i put both the exhaust AND intake if i have both or for some reason that wont work? thank you!

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There is no reason to do that, and it would be quite a pain to set up the timing, since the marks on both cams would then be wrong for the engine. If you want a completely different pair, or are looking for more power along with the AD functionality, use a pair of Hot Cams cams made for the 426.

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If memory serves me correctly I recall that the base circle on the 450 exhaust cam is different than the 426. Therefore, you cannot use the 450 exhaust cam on your 426. I may be wrong on this but I do remember that something is different!

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and this is probably a dumb question but are the cams in the "YFZ" 450 quads the same as in the "YZF" 450 bikes

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and this is probably a dumb question but are the cams in the "YFZ" 450 quads the same as in the "YZF" 450 bikes
No, the quad cams are similar to, or the same as, depending on the year, the WR450. You would loose performance going that way.
If memory serves me correctly I recall that the base circle on the 450 exhaust cam is different than the 426. Therefore, you cannot use the 450 exhaust cam on your 426. I may be wrong on this but I do remember that something is different!
You are wrong. There are hundreds of people who have been running the YZ450 exhaust cams in 400's and 426's, some of them for years now, who can attest to the fact that it not only works, it works very well.

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Just for reference the YZ426 F does have a different base circle diameter than the YZ450 F - I checked them today. Therefore, you will have to re-shim after installing a 450. Not a big problem but you will have to have a shim kit.

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Just for reference the YZ426 F does have a different base circle diameter than the YZ450 F - I checked them today. Therefore, you will have to re-shim after installing a 450. Not a big problem but you will have to have a shim kit.

Yes, you will certainly have to reshim. You don't need a whole kit. You will have to measure and then go get the shims that you need. The kit will keep you from one extra trip to the shop, but IMO the kits are too expensive. You will also have shims in the kit that you will not need on a YZ.

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Yes, you will certainly have to reshim. You don't need a whole kit. You will have to measure and then go get the shims that you need. The kit will keep you from one extra trip to the shop, but IMO the kits are too expensive. You will also have shims in the kit that you will not need on a YZ.
+1.

The way the shim kits break, you might also need one that isn't in the kit.

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the way i understood it, the yfz450 quad cam is the same as the yzf cam but it is retarded by being rotated a few degrees. or something like that. a lot of the yfz quad people do what they call the "cam mod", by taking it out and orienting it the right way, increasing power by a lot.

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The YZF and YFZ exhaust cams are not exactly the same. The decompression mechanism is timed differently between the two cams. Not a big deal but it is a difference. Also, there is a difference in the two decompression pin heights.

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The YZF and YFZ exhaust cams are not exactly the same. The decompression mechanism is timed differently between the two cams. Not a big deal but it is a difference. Also, there is a difference in the two decompression pin heights.
The pin length is how the decompression timing is accomplished. On earlier YZF quads and WRs, the cam shafts themselves were the same, and the cam timing was the ony difference between those and the YZ450F. To get enough of a reduction in the compression stroke, these cams have longer pins in the AD mechanism to compensate for the advanced timing run in the YFZ/WR engines. What some quad guys will do is retard the exhaust cam to YZ specs, and then grind down the pin to match the YZ pin, but I do not recommend doing this.

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ok cool! now i just need my shims to come in, because my local yamaha dealership didnt have any in stock:rant:

...but the guy did say the service department had some... do you think they would give me some out of their shop and when mine do come in they can just keep them???:cool: and i dont even care if they are used ones, cause i dont want to have to wait!

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ok cool! now i just need my shims to come in, because my local yamaha dealership didnt have any in stock:rant:

...but the guy did say the service department had some... do you think they would give me some out of their shop and when mine do come in they can just keep them???:cool: and i dont even care if they are used ones, cause i dont want to have to wait!

Some service guys will just swap what you need for what you've got...paticularly if you're a regular customer...sure can't hurt to ask.

Where in Cali are you and what thicknesses do you need?

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