timing 07 yz450f

so i was adjusting my valves and a friend came over and basically took the reigns on the project while i tinkered with my other buddys banshee. basically he ditched me and he has both my cams out for some reason and i cant seem to get the timing right. i got the piston at TDC and when i put the cams in and have the marks lined up with the case, the exhaust cam seems correct but when i put the intake cam in, the lobes are pointing down and wanting to open the valves. i must be doing something wrong. i have a servie manual but im not finding much help out of it. so basically can someone give me a good timing procedure please.

The lobes on both cams should point up and away from the head. Therefore, the exhuast lobes point up and forward and the intake points up and back.

To be even more clear, the exhaust marks are at 9 and 12 while the intake marks are at 12 and 3. Hope this helps.

feelin pretty stupid right now. didnt realize there were 2 punch marks on each cam. thanks a lot. now how tight should the cam chain be?

With the crank at top dead center as indicated by the "I" mark on the flywheel lined up to the notch on the magneto cover, your cam lobes should be pointing at the 2 O'clock and 10 O'clock positions as shown in the picture below. When oriented this way, the dots on the cam gear face will line up correctly. Note that there are more than one set of punch marks (dots) on the cam gear faces. Aligning the cam lobes as shown will get the correct set of punch marks aligned with the top machined surface of the head.

When checking to see if the timing marks line up, make sure the cam chain is pulled taut between the crank shaft and the exhaust cam, and then also between the two cam gears. Some people count cam chain pins between the top dead center of the two cam gears to make sure that they have the correct relationship between the two cams. At least for my 06' I get 12 pins that are entirely between the two teeth at the 12 O'clock position as also shown in the picture. Hope this helps.


The cams should be timed ONLY by the marks; one set of marks at 12:00 o'clock, and the other two at 9:00 (ex) and 3:00 (int) aligned with the head surface. Ignore everything else.

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