400 to 426 conversion, the easy way



48 replies to this topic
  • yz00

Posted April 19, 2012 - 05:54 PM

#41

The 426 piston uses a larger wrist pin, so you'd need the 426 rod
That would allow you to use the 400 crank.


ok so with the 426 cylinder/450 piston and rings you can use the 400 bottom end AND the con rod?
im trying my best to undertsand this all before i make a purchase...

and on top of all that the stock 400 head with decrompres exhast cam..?

Edited by yz00, April 19, 2012 - 06:00 PM.


  • umu24013

Posted April 20, 2012 - 07:05 AM

#42

ok so with the 426 cylinder/450 piston and rings you can use the 400 bottom end AND the con rod?

exactly. 400 bottom end + 400 con rod + 426 jug + 450 (5TJ) piston and rings

and on top of all that the stock 400 head with decrompres exhast cam..?

yes

  • yz00

Posted April 21, 2012 - 03:18 PM

#43

so will the 426 jug bolt up and use teh same gastkets as the 400 jug?

  • potman1980

Posted April 24, 2012 - 06:43 AM

#44

thanks for your help umu2.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • umu24013

Posted April 25, 2012 - 09:53 AM

#45

so will the 426 jug bolt up and use teh same gastkets as the 400 jug?

the base gaskets are the same. the cylinder head gaskets are different p/n

  • grayracer513

Posted April 25, 2012 - 10:00 AM

#46

the base gaskets are the same. the cylinder head gaskets are different p/n


The difference in the head gasket is the 95mm vs. 92mm bore size. The bolt patterns are the same between the 400 and 426.

  • yz00

Posted May 05, 2012 - 06:58 AM

#47

ok so one more question on this matter. on my 400 turns out the head is bad. my queston, i already have a 450 piston and a 426 jug but now what should i put on for a head? im guessing the 426 is only going to bolt on and would be best choice?

  • shorey400

Posted November 18, 2013 - 12:06 AM

#48

What is the difference with the 2s2 piston? Would this also work?

  • Billy.salmon

Posted July 03, 2016 - 07:55 PM

#49

I'm new here and know this is an old topic but can you use a big bore 450 piston





Related Content

Forums
Photo

YZ450F 03 Sparks driving me crazy by SirAttard


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies
Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Forums
Photo

100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies
Forums
Photo

First Hare scramble tips by dhend8


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.