yz exhaustcam on wr, need help with timing


21 replies to this topic
  • poffer

Posted September 09, 2007 - 07:56 AM

#1

Have searched this forum for help with timing and I found some tips but I still have some questions about this.

Stock the marks on camshaft are not 100% alligned as manual says but I counts 14 pins between the marks as shown in manual.

With the yz exhaust cam on I am able to allign the cams 100% as shown in manual exept that I now only can count 13 pins between the marks. Manual show 14 pins between marks...

What is the correct setting? Shall the marks on the cams be slightly out of allignment with 14 pins between the marks (as on stock wr 450) or shall it be 100% alligned with 13 pins between the marks (with yz exhaust cam on)

Hope someone can give me an answer before I need psycriatic help:crazy:

year 2003 wr450

  • maxtherat

Posted September 09, 2007 - 11:07 AM

#2

If you have a 03 wr and you are installing a cam for a 03 yz you put the cam in just like it shows in the manual. If you try to advance or retard the cam the decomp. will not work right and you elect. start will not work. Just tdc the motor, verify the dots on cam gear to the top edge of the head on intake cam and set exhaust cam so the dots line up on the head. On the decomp cam the difference in cam timing is made by how the cam gear is installed on the cam.

  • poffer

Posted September 09, 2007 - 11:49 AM

#3

Yes it is a 03 wr and the yz cam is also from a 03. I am not trying to advance or retard the timing, I'm only trying to get it right with this yz cam installed. As earlier said, if I allign the marks as the manual says I can only count 13 chain pins between the marks. Manual show 14..

If I put it in exactly as the stock cam was I count 14 chain pins as manual says but then the dots are slightly out of allignment. Also, in this possision the engine starts much easily with the electric starter but the kick starter is much harder to kick down than it was stock.

If i run it with the marks 100% allign as manual says but with 13 chain pins between the dots its much lighter to pull down the kick starter (as on stock) but its harder to start with the electric starter...

What is the right way to set the timing because its impossible to get the cams and chain possisioned as illustrated in the manual.

  • maxtherat

Posted September 09, 2007 - 04:42 PM

#4

sounds like you may not be exactly at TDC. I would just put it in just like you took out the wr cam. Does the manual actually give pin counts or are you just counting off the illustration? Don't put a lt of faith in the pictures. I have an 01 426 and my dots don't line up exactly but if I go 1 pin more or less it is really off the mark.

  • poffer

Posted September 09, 2007 - 09:56 PM

#5

I am exactly at TDC. The manual doesnt give pin counts, I'm counting off the illustration.

Talking about the dots that dont line exactly up, its the same on this 03 450 with stock cam. On the 400's and 426's you count 13 pins between marks to be sure that you are on wr timing and 12 pins if you are on yz timing.

Can anybody tell me if I should count 14 or 13 pins between the dots with yz cam installed?

  • WR_Dave

Posted September 10, 2007 - 06:07 AM

#6

"Yamaha of Australia offers downloadable manuals for older model motorcycles on their web site. Go to their web page and click on "support" at the top of the page, if this link does not direct you to the correct page. http://www.yamahaown...ook.com.au/?r=0 "

Go to the above site and follow the directions given above , select the YZ 450 in the year of choice and download it's manual and set the timing accordingly. If your going with the YZ cam it should be set to YZ specs. WR Dave.

  • poffer

Posted September 10, 2007 - 06:15 AM

#7

Thank you for the tips but I already have the yz 450 03 manual. Illustration is exactly the same as in wr manual and does not give me any answer to my questions..


edit: I found this: http://www.thumperta...light=yz timing shows 14 pins between the dots and says that you should not trust the dots on the cams and it also shows the right posission of the lombs if you are right on yz timing.

Also, does anyone know if the yz's are harder to kick start than a wr 450?

Here is how it looks with the cams 100% alligned as manual says (13pins) and how it looks slightly out off allignment (14pins)

http://www.eurofoto....php?aid=1569069

  • byggd

Posted September 10, 2007 - 02:23 PM

#8

Here are the instructions. Note they say the yz cam timing mark will not line up with anything. Also note the 14 pins between the timing marks.
http://s18.photobuck...0cam_Page_1.jpg

  • poffer

Posted September 11, 2007 - 01:22 AM

#9

If I set the timing like that the auto decomp doesnt work...

Isnt it anybody here on this forum that have done this mod and can tell me what is the right way to do it?

  • byggd

Posted September 11, 2007 - 07:28 AM

#10

Those are the EXACT instructions I followed when installing the YZ cam on my bike :thumbsup:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • poffer

Posted September 11, 2007 - 08:07 AM

#11

Ok, thanks. I really cant figure out what I'm doing wrong... Can you take a look at pic nr 1 under this link: http://www.eurofoto....php?aid=1569069 On this pic I have done exactly as discribed in the link you posted. It looks right compared to the pics in your link but auto decomp does not work with this allignment/timing. I bought the yz cam from my dealer and the package is marked with the 03 yz part number. Starting to wonder if I got a wrong cam. Was there any differances on the yz exhaustcams year 03-06 or are they all the same?

  • byggd

Posted September 11, 2007 - 10:45 AM

#12

I agree, the 14 pin picture you posted looks correct. Is the lower timing mark staying lined up? I know I had a heck of a time keeping it lined up when I did my install. Also is your valve clearance correct?

  • poffer

Posted September 12, 2007 - 09:03 AM

#13

I agree, the 14 pin picture you posted looks correct. Is the lower timing mark staying lined up? I know I had a heck of a time keeping it lined up when I did my install. Also is your valve clearance correct?


Yes the lower timing mark are 100% lined up and the valve clearence is also right.

I talked to a mechanics at yamaha scandinavia today and I also mailed him the instructin with pics how to do this ( http://s18.photobuck...0cam_Page_1.jpg )and he told me that this way to do it was wrong. The cam lombs on the exhaustcam should be pointet/directed a little bit up and not lined exactly opposite with the lomb on the intake cam if you understand what I meen.

I had the stock wr camshaft back on again today to compare and stock the lombs are alligned like the pic in the instruction how to set the yz timing correct....

Thinking back on my old wr400 I think that the guy I talked with today is right. When I yz timed this bike I rotated the exhaustcam 1 tooth clockwise, counting 12 pins instead of 13 as it was with stock wr timing. The exhaustvalve on the yz are opening a little bit later than wr timing and they also stands open longer making the filling more optimal. Correct me if I'm wrong.

I have now the yz cam on, alligned 100% on all marks as manual says but I only counts 13 chain pins between the upper "allignment marks". Bike pulls strong on mid and top but it feels like I'm loosing a little bit power down low. Think I stay with this timing.

  • jbrooks26

Posted September 12, 2007 - 10:00 AM

#14

If you are swapping out an 03 WR cam for an 03 YZ cam then you do not need to count pins. Don't trust the pictures in your manual for timing, they could be generic pictures simply to give you an idea of what the manual is telling you to do. You will not find it in any manual that there are so many pins between the timing marks, this is somthing that people came up with to do this modification on the 02 and earlier WR. If you currently have your 03 YZ cam installed in your 03 WR with the timing marks lined up with the edge of the head at TDC then you are timed correctly. Losing a little on the bottom is a side effect of this modification, it is a characteristic of the WR that is lost when changed over to YZ timing. It sounds like you are timed correctly and I would leave it at that. Hope this helps.

Josh

  • poffer

Posted September 12, 2007 - 10:22 AM

#15

Thank for your reply:thumbsup: I think I have it right now so I'l stay with this timing.

Not trying to be a smartass but I dont think this instruction http://s18.photobuck...0cam_Page_1.jpg can be used if you want to yz your wr 450.

  • byggd

Posted September 12, 2007 - 11:28 AM

#16

Yes you're right. The instructions are only good for updating a 400/426 as stated at the top. My apologizes, for some reason I thought you were working on an earlier model probably becasue you were only installing the exhaust cam. Is there a reason you didn't do both cams??

  • jbrooks26

Posted September 12, 2007 - 12:43 PM

#17

I believe the intake cam is still identical on the YZ and WR in the 450's. No reason to change both unless you are going to an aftermarket cam set.

  • poffer

Posted September 12, 2007 - 12:49 PM

#18

We did not change the intake cam on the 400 and 426 so I guessed there was no reason to do it on the 450 either but maybe I'm wrong. As far as I can se the only reason to swap the wr cam for a yz on the 450 is because of the autodecomp system on this models.

But I cant see how the instructions here http://s18.photobuck...0cam_Page_1.jpg can be the right way to do it on a 426 or 400 either. If you yz time on of this model by turning the exhaustcam one tooth clockwise it wont look like it says in the linked instrucktion above. It would only look like that if you swap the 00-02 stock wr cam with a 03 450 wr exhaust cam (to get autodecomp on the 400 and 426 models)

  • jbrooks26

Posted September 12, 2007 - 04:19 PM

#19

You are confusing two different mods. The mod your link is for swaps the 03 YZ cam into the 02 and older WR heads. This was done as you say simply to get the Auto decomp and YZ timing. There was a modification for the 02 and earlier models simply for getting YZ timing on a WR before auto decomp ever came along. This mod rotated the WR exhaust cam clockwise one tooth to achieve YZ timing in the WR. I hope this clears up the confusion a bit.

Josh

  • poffer

Posted September 12, 2007 - 09:13 PM

#20

You are confusing two different mods. The mod your link is for swaps the 03 YZ cam into the 02 and older WR heads. This was done as you say simply to get the Auto decomp and YZ timing. There was a modification for the 02 and earlier models simply for getting YZ timing on a WR before auto decomp ever came along. This mod rotated the WR exhaust cam clockwise one tooth to achieve YZ timing in the WR. I hope this clears up the confusion a bit.

Josh


No, I'm not mixing two different mods. Sorry for my bad english but what I ment was that this instruction ( http://s18.photobuck...0cam_Page_1.jpg ) can NOT be the right way to put a yz 450 cam on the wr 400 og 426 either. The pic shows the lombs on both camshaft almost 100% alligned with each other and the pic says that this is how it should look when the yz 450 cam is installed right. If you take a look on a 400 or 426 with stock cam, set for yz timing it wont look like the pic. I think the pic show correct wr timing and not yz.




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.