Please need advice asap!

12 replies to this topic
  • panteramatt

Posted October 15, 2004 - 12:57 PM


I have a chance to get either a yzf400 or 426 motor to put in my 400ex frame. Which one would beb better for an atv or is there much difference? Whats the biggest bore that a 400 can go to and be reliable?

  • sirthumpalot

Posted October 15, 2004 - 02:22 PM


The later the better.

  • panteramatt

Posted October 15, 2004 - 08:08 PM


Why is that, I need some info.

  • Chipstien

Posted October 15, 2004 - 08:16 PM


More cc's and a better clutch. Bigger radiators too if you are getting them with the motor.

  • panteramatt

Posted October 16, 2004 - 04:39 AM


But cant a 400 be bored out just as much as a 426?

  • SureBlue

Posted October 16, 2004 - 04:56 AM


But cant a 400 be bored out just as much as a 426?

But you asked:
"I have a chance to get either a yzf400 or 426 motor to put in my 400ex frame".
Why would you then chose 400 and bore it up if u can have 426? :cry:

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  • panteramatt

Posted October 16, 2004 - 05:08 AM


Heres the deal. I have a 250r and a 400ex rolling chassis. I can get a 250r frame with a yzf400 motor already modded and ready to roll, or can get a good deal on just a yzf426 motor and have to mod my 400ex to fit and buy some other things.So please help me out!

  • Fastest1

Posted October 16, 2004 - 05:10 AM


What year 426 motor? The 2001 and later has a splined crankshaft snout, whereas the 2000 and earlier have a keyway for the counter balancer gear, Yes a 426 jug and piston will fit a 400. Better carb on a 2000 and later model too.

  • panteramatt

Posted October 16, 2004 - 05:32 AM


OK, will a 2001 and later carb bolt directly onto a 98-00? Also I see a wiseco 444 kit on ebay that comes with the cylinder, piston and all for the 426, will that bolt directly onto a 400

  • sirthumpalot

Posted October 16, 2004 - 10:03 AM


I think the rods changed at some point, but I don't remember what year?

  • panteramatt

Posted October 17, 2004 - 06:23 AM


Anyone else, I need some info.

  • SFO

Posted October 17, 2004 - 09:24 AM


426 gets the larger id rod small end.
426 rod less prone to shed its small end than a well used 400.
400 has a closer first and second gear which results in a closer ratio gearset for the 400 which might be adventageous for the 4wheeler.
Upgrade the rod to a failcon for a stroker cr-f and get the bushed small end.
A 97 mm kit will require fittment of the 426 rod, or the above falicon choice.
I would rebuild any motor before fittment, as there is no gaurantees.

  • SXP

Posted October 17, 2004 - 09:17 PM


SFO - What's the end cubic capacity after the CR-F stroker and 97 mm overbore? Thanks.

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