putting engine back together......

7 replies to this topic
  • tammie

Posted March 14, 2005 - 10:15 AM


1999 YZ400

ok I got my cylinder head gasket in today so im ready to put the cylinder head back on...........i replaced the timing chain.......

can i have some advice...tips..........from those that have done this before......setting up cam timing....etc....

any probs i might run into ...........this was my first time taking this stuff apart.......

thanx guys


Posted March 14, 2005 - 10:30 AM


when i put my '00 426 motor back together i thought it was pretty easy. if you have a manual then just go by the book. thats what i did and mine came out perfect. good luck and have fun.

  • bushy

Posted March 14, 2005 - 01:19 PM


rtfm :)

  • tammie

Posted March 14, 2005 - 01:20 PM


oh i forgot to mention i had the stator and fly wheel off too...........when i put the cylinder head back on the piston was at TDC....but now that ive put the stator back on im about to put the flywheel back on how do i m ake sure the piston is still at tdc when installing the flywheel? the flywheel can only go on one way right ........that little thing(woodruff key) how does that work what does it do?

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  • tammie

Posted March 14, 2005 - 01:28 PM


rtfm :)

OBVIOUSLY!!! ........but i was just asking as this is my first time and some of you have alot more experience and may have some tips ........i wouldn't have posted here if I hadn't already read the manual.........im just asking for additional advice from those who have done this.........
I thought thats what this forum was for..........asking questions .......

thanx for the sarcasm anyways........ sorry Im not perfect :)

  • LJ

Posted March 14, 2005 - 01:52 PM


I haven't done the top end yet on my '99 yz400, but I read an interesting tip in I think Dirt Bike Magazine or Dirt Rider.

They said to instal the piston in the cylinder before you put the cylinder on the bike. Leave the piston hanging down enough to instal the piston pin and circlips when installing the cylinder.

I've done a few 2-stroke top ends and sometimes it is kind of tricky getting the rings compressed and the piston into the cylinder while the piston is already attached to the rod. It seems to me it would be easier to do this on the bench and then just slide the piston pin through the piston when installing the cylinder on to the bottom cases.

  • tammie

Posted March 14, 2005 - 02:57 PM


thanx but i only took the cylinder head off, didn't take the cylinder and piston out at all...........so i don't have to worry about that.........
i just cleaned all the carbon off the top of the piston........

  • 02YZ426

Posted March 14, 2005 - 02:57 PM


Remember to stagger the rings on the piston before you install it. If you dont, your going to have a smoker. Also, make sure you use a torque wrench, and torque the head and cam cover down. Very important.

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