02 426/03-05 450 interchagibility?

12 replies to this topic
  • dirtbikekidd

Posted May 26, 2009 - 02:40 PM


Hey, First post here.
i currently have an 2002 yz426f, and have had it since christmas of 08.
but i dropped all three intake valves yesterday comming home on a long straightway, going WTFO.
But anyways my question is Will 03-05 450 top part, valve part interchange with an 02 426?
Thanks in advance for all replies.

  • grayracer513

Posted May 26, 2009 - 03:25 PM


Apparently, it can work, but only if you use a 450 crank, piston, and complete top end. The head won't fit the 426 cylinder, and so on, downward. No proof of that, either, so my normal sort answer is no.

In any case, it's likely to be cheaper to rebuild as a 426, since you have the option of using the stainless steel valves from a 2000 model (use only the 2000 model springs with this).

The head can often be repaired for less than a bare replacement can be bought for. Contact EDCo.

It sounds like you seized the intake cam, or the timing chain jumped for some other reason.

  • dirtbikekidd

Posted May 26, 2009 - 03:32 PM


Ok thank you.
Is there any advantage switching over to stainless in terms of reliability and performance? Such as i keep finding my self looking for more torque, rather than my back tire spinning out.
I did adjust the valves a couple days ago..
left intake was loose, middle ok, right intake tight.
from what the head looks like the middle did the most damage, which left me stumped.

  • grayracer513

Posted May 26, 2009 - 05:57 PM


The biggest advantage to the OEM SS valves is that you can buy all 5 of them for less than the cost of two titanium intakes. They will last at least as long and cost (or add) nothing in terms of performance in a stock YZ426.

  • dirtbikekidd

Posted May 27, 2009 - 05:39 PM


Would the 450 oem valve fit on the 426?

  • grayracer513

Posted May 27, 2009 - 06:04 PM


Would the 450 oem valve fit on the 426?


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  • TIG88

Posted May 28, 2009 - 01:29 AM


If your back tire is spinning out too much, get a flywheel weight. Its not from lack of torque that this is happening, but rather the opposite. Too much power.

  • dirtbikekidd

Posted May 29, 2009 - 08:32 PM


I dont see how that could be happening, the bike is still stock, aside from tires and chain...
but what weight would you recommend?
i ride mostly 50% desert 50% singletrack..

  • Cavi

Posted May 30, 2009 - 07:51 PM


what gearing are you running?

  • buzzgrizz

Posted May 31, 2009 - 11:24 AM


I know this is a little off topic for this thread but i need to know will a newer style 06 and up front fender fit with the old style nuber plate?

  • grayracer513

Posted May 31, 2009 - 12:59 PM


Not precisely, no. The new plate will fit your bike, though.

  • buzzgrizz

Posted May 31, 2009 - 08:01 PM


yes the new plate will fit but it will be hard to get pre prints for the new number plate and the old 426 rear nember plates

  • dirtbikekidd

Posted June 01, 2009 - 03:53 PM


what gearing are you running?

i am currently running 14/50, but plan on getting a 14/46 or 47 or 48

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