400/426 head

2 replies to this topic
  • Br1ggs

Posted June 29, 2016 - 10:34 AM


Hey guys, sorry if this is the wrong place, my first day as a registered user of TT! I bought a yz400 a month or so ago that needed rebuild, rebuilt the bike only to find out my valves are FUBAR'd. not anywhere in town I'd trust to have my heads redone, and looking at the rest of the motor not sure I would trust the head to be in good shape anyways (was hoping for just bent valves but im losing hope)  I have been itching to ride this bike since I bought it and I think this will be my last part. Let me know!



Edited by grayracer513, June 29, 2016 - 03:30 PM.
remove offer to buy

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  • toten

Posted June 29, 2016 - 10:55 AM


I've read that you can swap the cylinder and head from a steel frame 450 onto a 400/426 using a 426 piston. No personal experience though.

  • grayracer513

Posted June 29, 2016 - 03:29 PM


1) This is the right place to ask about a YZ400


2) This is the wrong place to put a want ad.  As stated in the rules you agreed to follow when you registered, all offers to buy, sell, or trade must be placed in the classifieds (thus the edit)


3) You could use a 450 head on the 400/426, but it requires using a 450 cylinder and piston.  It's not quite a bolt up thing, exactly, and it's expensive.  On top of that, you give up the ability to use the low cost OEM stainless steel valves from the 400.


4) Your head is probably more serviceable than you think.  I recommend Engine Dynamics in California, or Millennium Technologies closer to you.  Google them, call them up, and talk to them about what the problem is. 

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