Cam Question?


10 replies to this topic
  • WRototiller

Posted April 03, 2005 - 10:01 PM

#1

I just bought a 98 WR 400, and wanted to check the cam timing. And set it to YZ time if it had not been done . I got it all apart and lined the " l " mark up in the hole, the cams are pointing away from each other. The exhaust,(front) cam punch marks line up at 9, 12, and 3:00. The intake (rear) cam is not lined up. It looks to be one tooth off in the clockwise direction. The motor seems to run pretty strong. So should I set the intake cam to line up at 9, 12, & 3:00, and then move the exhaust cam 1 tooth clockwise? I'm kind of suprised it ran this well, but this is my first 4-stroke and i'm not sure what to expect.
Thanks

  • scott_h

Posted April 03, 2005 - 11:05 PM

#2

'tiller,

My 98 WR cams marks did not line up perfectly at 9, 12 & 3 o'clock, but I found that if I moved them one tooth either way on either cam trying to them lined up, it only made them look worse. I think this may be a byproduct of tolerance buildup in the manufacturing process. The best you can do is make sure, you've got cam chain tensioner engaged to take the slack out when your checking the timing and get it as close as you can. Once you're satisfied with the WR timing mark the chain/sprocket alignment and then rotate the exhaust cam one tooth clockwise for YZ timing. Here's how my 98 looks with WR timing set.

Posted Image

  • JMathis

Posted April 04, 2005 - 03:24 AM

#3

Does this 400 have the auto decomp cam installed. If so, that is how it should be. When you install the auto decomp cam you have to set it one tooth off so it does not look right when it is in there but it runs awesome and starts great.

  • WRototiller

Posted April 04, 2005 - 04:02 AM

#4

Thanks fo the pic. The intake cam really looks to be one tooth off, I'm going to try to move it just to make sure. I'll see what happens. I just don't want to wreck anything, and it seemed weird enough that I figured I should ask a few questions.
Thanks

  • jchantzWR400F

Posted April 04, 2005 - 06:41 AM

#5

'tiller,

My 98 WR cams marks did not line up perfectly at 9, 12 & 3 o'clock, but I found that if I moved them one tooth either way on either cam trying to them lined up, it only made them look worse. I think this may be a byproduct of tolerance buildup in the manufacturing process. The best you can do is make sure, you've got cam chain tensioner engaged to take the slack out when your checking the timing and get it as close as you can. Once you're satisfied with the WR timing mark the chain/sprocket alignment and then rotate the exhaust cam one tooth clockwise for YZ timing. Here's how my 98 looks with WR timing set.

Posted Image



Actually, in the picture, you appear to have yz timing. I count 12 pins between 12:00 marks.

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  • WRototiller

Posted April 04, 2005 - 08:33 AM

#6

I wish I had a digital cam so I could show a picture of mine. I still would like some input on why the intake cam could be off, and it still ran decent? And unless scott_h has yz cams in his, the marks wouldn't line up that nice, Would they?
Thanks

  • Math

Posted April 04, 2005 - 11:25 AM

#7

Actually, in the picture, you appear to have yz timing. I count 12 pins between 12:00 marks.


I think you're right. According to the WR's service manual, and for a "WR-timed" WR, the E mark on the exhaust cam really should be flush witht the surface and so should be the I mark on the intake. We should count 13 links between the top marks if you were WR timed.

  • scott_h

Posted April 04, 2005 - 11:35 AM

#8

You guys are right. Looks like I got the labels on my pictures swapped.

Scott

  • WRototiller

Posted April 04, 2005 - 04:14 PM

#9

So does anyone have a picture of their WR, YZ-timed with the " l " mark lined up?

  • Sylvain

Posted April 04, 2005 - 11:23 PM

#10

Would it be possible to have a picture of 2002 wr 426 with a 2003 YZ 450 auto decomp cam installed ?

I have a few prints of various set up but I want to make sure my cam are properly set up.

Thanks

  • Sylvain

Posted April 08, 2005 - 11:56 PM

#11

So does anyone have a picture of their WR, YZ-timed with the " l " mark lined up?



bumpy




 
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