question on 426 cam adjustment HELP!!

3 replies to this topic
  • okieonayamaha

Posted April 26, 2004 - 10:39 AM


yesterday I tore my motor down on my 2000 426 because we heard a knocking noise we thought it was the piston maybe or a bearing maybe siezed it was the first time the motor has ever been torn down we took everything off except splitting the cases of course but it was our first time to ever tear down a 4-stroke so of course we didn't find anything wrong so when we put it back together we tried to get the cams back just right but did it wrong there is no compression now and it feels like it is blowing out the carburator like it is 180 degrees off just needed to know if anybody knows anything about getting it timed right again thanx for the help.

  • John_Lorenz

Posted April 26, 2004 - 10:53 AM


You need to get the Piston at top dead center at the Compression stroke.

This means the eyelet on the left side (Stator Side) you should have the timeing mark aligned. The Cam Lobs will be opposed from each other. There are two distin marks on the Cam gears to align.

Do you have a Manual

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  • okieonayamaha

Posted April 26, 2004 - 02:48 PM


in the manual the only spot I can find that talks about it said after you align everything take a wrench and turn the crankshaft counter clockwise several times when we did that nothing lined up should we just lay each cam in there with the lobes facing away from eachother and line the mark on the stator and try it like that.

  • tctrailrider

Posted April 26, 2004 - 03:52 PM


Read motomans tech articles about YZ timing. It will clear up some issues on the top end. Line up the I mark on the flywheel in the inspection hole (just to the right of the H mark). Set the intake cam with the punch marks at 3-12-9 oclock. Set the exhaust cam off that. 13 pins between 12 oclock punch marks for WR timing, 12 pins for YZ. The lobes on both cams will be pointing out. When you install the chain tensioner both cams will rotate a little clockwise so allow for this.

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