Swapping YZ Cylinder Head on WR


9 replies to this topic
  • Power

Posted January 15, 2009 - 09:47 AM

#1

So I have a 2005 WR 450, and while on the hunt for more power I found a 2004 YZ450 Complete Cylinder Head. Now I know this will bolt right up to my 2005 WR 450, but will the e-start still function normally? I've heard stories about when people swapped YZ cams into their WR, the bike wouldn't e-start very good. I was just wondering if anyone has done this mod to their bike and if so, was the performance worth the cost, and did your e-start work? Thanks!

  • brad the best

Posted January 15, 2009 - 05:42 PM

#2

i have read , if you do i believe its the blue wire mod the e-start problem is gone . also have it jetted properly .

i think its more of a cold start were the electric is not that great .

personally with wr cams mine doesn't start that easy off the button , one kick and it goes but when its cold it just doesn't like to start on the electric without say 5-7 seconds cranking .

hot its fine .

  • Power

Posted January 16, 2009 - 11:06 AM

#3

I'm thinking the YZ head will give it the snap that the 2004's had on a 2005 WR 450. The power they had was amazing! I'm going to wait for some more responses, because I dont want to drop the money on a new cylinder head and it turns out that my electric start doesn't work. :thumbsup:

  • SJMC_DON

Posted January 16, 2009 - 11:22 AM

#4

The e-starting issues with the YZ cam swap are related to the auto decomp pin/lobe on the YZ exhaust cam... still undecided but it's either taller or timed different resulting in more compression being dumped than what the WR exhaust cam does.

Kick start your WR and then kick start a YZF... you'll immediately notice the YZ is easier to kick.

The problem as I understand it, is that when e-starting the WR more compression is required because the e-start simply does not move the piston fast enough. The WR with the YZ cam in it will kick easier and kick start immediately and the power gains are awesome.

My opinion, and this is my opinion as others have different opinions, you would be better off purchasing a set of Hot Cams specifically made for the WR that will retain the needed compression for the e-start to work. They (Hot Cams), claim to have cams that do this.

I have done the cam swap from WR to OEM YZF, I don't know everything but I am not a newb idiot either, I got frustrated enough with the e-start issues and did as much research as I could until finally realizing that no matter what I did I was not going to get the e-start to work the way I wanted with the OEM YZ cams in it.

The blu/wht wire mod is something different and while it's a worth while mod on any WR regardless of what cams you have, it will not help address the e-start issues related to using YZF ex cam...

Good Luck:ride:

  • beezer

Posted January 16, 2009 - 11:58 AM

#5

I think for all intents and purposes the YZ head is identical to the WR head.

The cams are different.

I have YZ cams in my WR and they make the e-start work harder but it still works. When the bike is cold I use my kickstarter.

The YZ cams really make the WR bark.

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  • PBDBLUE

Posted January 16, 2009 - 11:59 AM

#6

I have a YZ cam in my '04 and it estarts fine. Probably used the kickstarter less than a handfull of times since I bought it new. I agree with you though the '04 motor was arguably one of the best at least for desert riding.

  • 123BigcoopDawg576

Posted January 16, 2009 - 12:07 PM

#7

The e-starting issues with the YZ cam swap are related to the auto decomp pin/lobe on the YZ exhaust cam... still undecided but it's either taller or timed different resulting in more compression being dumped than what the WR exhaust cam does.

Kick start your WR and then kick start a YZF... you'll immediately notice the YZ is easier to kick.

The problem as I understand it, is that when e-starting the WR more compression is required because the e-start simply does not move the piston fast enough. The WR with the YZ cam in it will kick easier and kick start immediately and the power gains are awesome.

My opinion, and this is my opinion as others have different opinions, you would be better off purchasing a set of Hot Cams specifically made for the WR that will retain the needed compression for the e-start to work. They (Hot Cams), claim to have cams that do this.

I have done the cam swap from WR to OEM YZF, I don't know everything but I am not a newb idiot either, I got frustrated enough with the e-start issues and did as much research as I could until finally realizing that no matter what I did I was not going to get the e-start to work the way I wanted with the OEM YZ cams in it.

The blu/wht wire mod is something different and while it's a worth while mod on any WR regardless of what cams you have, it will not help address the e-start issues related to using YZF ex cam...

Good Luck:ride:


Text Book answer...I would love to do the YZ cam but the e-start is just not worth giving up.

  • Power

Posted January 17, 2009 - 08:22 PM

#8

I'll probably look into Hotcams then, instead of spending my money on a YZ450 top end. Thanks for the info guys!

  • clark4131

Posted January 17, 2009 - 08:52 PM

#9

The top ends are the same...the difference is in the cam grind and the transmission...SC

  • Power

Posted January 18, 2009 - 08:21 AM

#10

The top ends are the same...the difference is in the cam grind and the transmission...SC


Well, and the holes for the AIS System... :thumbsup:

Anyways thanks for the info!!




 
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