Cam shaft timing


4 replies to this topic
  • stroker101

Posted September 05, 2012 - 04:11 PM

#1

hey guy's, i'm having an issue getting the exhaust and intake cams timed with the crank shaft.
i have the "middle" mark (there's 3) lined up w/ the mark on the ignition cover, i can get the intake cam where it needs to be, but when installing the exhaust cam, the cam lobes engage the exhaust valves after installing the cam cover. no matter what i tried, i'm failing at getting this engine finished.
.
shouldn't the cam lobes on both cams not be in contact with the valve buckets at TDC? what am i doing wrong?
please help me!!!

LOL

thx in advance!!!

(working on my 2009 YZ450F / repaired 5th gear issue, installed new top end)

  • stroker101

Posted September 05, 2012 - 04:58 PM

#2

i figured it out. i needed my magnafying glass to see the other dimple on the exhaust cam sprocket. sorry for the panic.

can a moderator delete this post for me?

thx!!!

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  • grayracer513

Posted September 05, 2012 - 08:28 PM

#3

The middle mark is the wrong one.

The mark at the far right of the three is TDC. From left to right, or as they appear when the engine turns, the first two are ignition timing references, and if you look, they'll be joined by a horizontal line, making them an "H". The third mark, or the "I", is TDC.

Could explain part of your problem.

  • stroker101

Posted September 05, 2012 - 10:59 PM

#4

The middle mark is the wrong one.

The mark at the far right of the three is TDC. From left to right, or as they appear when the engine turns, the first two are ignition timing references, and if you look, they'll be joined by a horizontal line, making them an "H". The third mark, or the "I", is TDC.

Could explain part of your problem.


Thx grayracer513. I went and doubled checked what I did to your info and with the magnafying glass, I saw the "H" as you described. I have the cams timed correctly now. Previously, I had an issue with the dimples on the exhaust cam sprocket.
The one that I needed to be "horizontal" was very faint to the naked eye. Using the magnafying glass enabled me to see that dimple and install the cam correctly.
I've rotated the engine several times and the cams are in time with the crank. I will install the engine in the frame tomorrow.


Thx for your help

  • stroker101

Posted September 06, 2012 - 09:45 AM

#5

Thx grayracer513. I went and doubled checked what I did to your info and with the magnafying glass, I saw the "H" as you described. I have the cams timed correctly now. Previously, I had an issue with the dimples on the exhaust cam sprocket.
The one that I needed to be "horizontal" was very faint to the naked eye. Using the magnafying glass enabled me to see that dimple and install the cam correctly.
I've rotated the engine several times and the cams are in time with the crank. I will install the engine in the frame tomorrow.


Thx for your help



The bike is back together and started in 3 kicks. Sounds sweet. Now I need to break it in





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