yz cam..wr timing???


15 replies to this topic
  • dmoney1074

Posted April 08, 2007 - 03:14 PM

#1

Doea anyone know if I can keep wr timing (13 links) if I install an 03 yz autodeomp cam??? Also I'm putting it in my 426, so will I have to reshim???

Thanks!!!

  • Fryboy

Posted April 08, 2007 - 07:25 PM

#2

No you won't be able to keep your WR timing with a YZ cam. YZ timing with YZ Cam or WR timing with WR cam.

Yes you will have to reshim after the install.

  • dmoney1074

Posted April 08, 2007 - 07:52 PM

#3

So ill need 12 links between the dots???...

  • Fryboy

Posted April 08, 2007 - 09:40 PM

#4

According to the FAQ http://www.thumperta...ighlight=WR FAQ


12 teeth would be for YZ timing and 13 would be for WR timing.

Hope that helps. I believe all this is in the manual. I wouldn't do this without one.

  • Thermos O flask

Posted April 09, 2007 - 03:37 AM

#5

Mate, I think when you fit an 03'yz cam you will have 13 pins because yamaha have all ready moved the cam(so to speak)the gear stays in the same place, the dots line up with the head surface like normal.You will only have 12 pins when you move the WR cam to YZ timing on a wr400/426.But your FITTING a YZ cam so its just bolt in as normal.:thumbsup: (even if the teeth are a different pitch to the chain).

  • byggd

Posted April 09, 2007 - 07:11 AM

#6

Here are the instructions including pictures of the yz cam properly installed. As you can see 14 pins is correct. Yes, you will need to re-shim .1-.2 mm thicker.

http://s18.photobuck...0cam_Page_1.jpg

  • dmoney1074

Posted April 09, 2007 - 09:54 AM

#7

Here are the instructions including pictures of the yz cam properly installed. As you can see 14 pins is correct. Yes, you will need to re-shim .1-.2 mm thicker.

http://s18.photobuck...0cam_Page_1.jpg


I'm sorry I have to ask this, but how do you know its 14 pins? Are you a mechanic? I honestly dont mean to insult you, but I cant just take the advice of anyone... you know? Where did you get your information, or did you just use trial and error?

Thank you very much for the replies! :thumbsup:

  • byggd

Posted April 09, 2007 - 12:59 PM

#8

I understand your skepticism. If you follow the link I posted you can plainly count the 14 pins between the timing dots. By the way I didn’t write the instructions but they have been used by many including myself to correctly do this mod. And yes I am a mechanic, working on everything with a spark plug from the time I was in the 9th grade and I just turned 46. If you are interested here is a link showing the power curves before and after the mod.
http://s18.photobuck...0cam_Page_2.jpg

[COLOR="Red"]EDIT Keep in mind I am counting the pins not the teeth. 14 pins = 13 teeth. [/COLOR]

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  • byggd

Posted April 09, 2007 - 01:06 PM

#9

Mate, I think when you fit an 03'yz cam you will have 13 pins because yamaha have all ready moved the cam(so to speak)the gear stays in the same place, the dots line up with the head surface like normal.You will only have 12 pins when you move the WR cam to YZ timing on a wr400/426.But your FITTING a YZ cam so its just bolt in as normal.:thumbsup: (even if the teeth are a different pitch to the chain).

Easy mate. I think you are correct if installing a yz cam on a 03 or newer wr but if you run 12 pins on a 01-02 you may end up with bent valves.

  • brucifer

Posted April 09, 2007 - 01:22 PM

#10

OK I will ask the stupid question. Don't the cam gears have index marks that line up with the head, while the piston is on TDC. What difference does it make how many pin there are if the marks are liked up?

  • byggd

Posted April 09, 2007 - 01:29 PM

#11

OK I will ask the stupid question. Don't the cam gears have index marks that line up with the head, while the piston is on TDC. What difference does it make how many pin there are if the marks are liked up?

In reading the instructions you will note that when installing a stock 03 yz ex cam into an earlier bike the marks on the ex cam will line up with nothing. Now if you are using hot cams that another story.

  • brucifer

Posted April 09, 2007 - 03:26 PM

#12

I did not know that. You mean when I installed the auto decompression cam in my 426 by lining the marks I have it out of time? It has run great for 2 years. Maybe i got it right by mistake. Can't remember, drawback from hitting my head so many times. Next time I take it apart I better check.

Please DON'T any one use this entry as fact! :thumbsup:

Yamaha has instructions on how to put a 03 cam in a 426? or you talking about the instructions on a link? That is why I like Lobe Centers.

  • byggd

Posted April 10, 2007 - 03:45 AM

#13

I did not know that. You mean when I installed the auto decompression cam in my 426 by lining the marks I have it out of time? It has run great for 2 years. Maybe i got it right by mistake. Can't remember, drawback from hitting my head so many times. Next time I take it apart I better check.

Please DON'T any one use this entry as fact! :thumbsup:

Yamaha has instructions on how to put a 03 cam in a 426? or you talking about the instructions on a link? That is why I like Lobe Centers.


I was referring to the instructions from the link. Again I didn’t write them I just followed them and my bike runs awesome!
http://s18.photobuck...0cam_Page_1.jpg

Also here is an old thread on this subject. As you will read there was much confusion but in the end 14 pins is correct. I think the sticky FAQ thread needs correcting.
http://www.thumperta...6&highlight=cam

  • Thermos O flask

Posted April 10, 2007 - 05:08 AM

#14

I have never fitted an '03 yz exhaust cam into a 400/426 so the marks may not line up,i just assumed they would :worthy: .BUT reading the link it says there are differences,mainly the lobe center and the teeth pitch,from what i'v read the timing chain will wear out faster and thats why i'v just fitted a hotcams yz cam into my wr400 and it has the correct chain teeth pitch(hotcams lists a different cam for '03 on).But hey..what ever works. :thumbsup:

  • brucifer

Posted April 14, 2007 - 02:50 PM

#15

Yes you made the right choose :thumbsup: Don't the hot cam come with adjustable gears? The ones i put in my 250 did. You can move the Lobe Center and get just the curve you want,IF you want to take the time.

I just want to ride mister. HEHE that is a neet comercial.

  • Thermos O flask

Posted April 15, 2007 - 03:36 AM

#16

Yeah mate ,only the inlet cam comes with the vernier gear.I only got the exhaust cam.I'm going to see how it goes with the exhaust first.I don't realy need any more power i'm having trouble hanging on as it is!:thumbsup:




 
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