yz exhaustcam on wr, need help with timing
Posted September 09, 2007 - 07:56 AM
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
Posted September 09, 2007 - 11:07 AM
Posted September 09, 2007 - 11:49 AM
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.
Posted September 09, 2007 - 04:42 PM
Posted September 09, 2007 - 09:56 PM
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?
Posted September 10, 2007 - 06:07 AM
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.
Posted September 10, 2007 - 06:15 AM
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)
Posted September 11, 2007 - 01:22 AM
Isnt it anybody here on this forum that have done this mod and can tell me what is the right way to do it?
Posted September 11, 2007 - 07:28 AM
Posted September 11, 2007 - 08:07 AM
Posted September 11, 2007 - 10:45 AM
Posted September 12, 2007 - 09:03 AM
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.
Posted September 12, 2007 - 10:00 AM
Posted September 12, 2007 - 11:28 AM
Posted September 12, 2007 - 12:43 PM
Posted September 12, 2007 - 12:49 PM
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)
Posted September 12, 2007 - 04:19 PM
Posted September 12, 2007 - 09:13 PM
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.
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.