can you put a 250 in a 426

10 replies to this topic
  • yz426fride

Posted March 25, 2011 - 05:29 PM


i have a 02 426f and i was wondering if it would be possible to put a yamaha 250 in the frame, i think the 426 may have been too much bike. please let me know if you have any experience with this


  • 02WR426Cali

Posted March 25, 2011 - 05:51 PM


Of course anything is possible it would just take some fab and maybe some new parts. I think the first few years of the 250f are real similar to the 400/426 but I doubt it will bolt right in. I don't know enough technically about the differences so I can't give you any facts, but you CAN do it.

The question is why? If the 426 is too much bike right will want it someday.

  • dalonar

Posted March 25, 2011 - 06:12 PM


426 is too much? why not just roll the throttle tube so that you cant twist it all the way? 2 weeks of hard riding and you'll be fine with the 426.

  • yz426fride

Posted March 25, 2011 - 06:12 PM


to answer your question, i want to put a 250 in it because i found a cheap 250 that i could throw in while i rebuild the 426 maybe?

  • dalonar

Posted March 25, 2011 - 07:10 PM


oh, you have WAY more ambition than i would have. pretty sure none of the electronics would cross over. let alone bolt up

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  • yz426fride

Posted March 25, 2011 - 08:05 PM


what would i have to do to get the electronics to match up. i can make whatever mounts i have to on a CNC machine at work so i dont think that will be too hard. but what would i have to do with the electronics

  • grayracer513

Posted March 25, 2011 - 08:25 PM


Won't fit without cutting and fabbing a taller "Y" section where the frame splits at the bottom of the down tube, which, of course, is your oil tank.

Overall, a really bad idea.

  • ttr250dude

Posted March 26, 2011 - 02:20 AM


You could sell your 426, buy a newer year 250f, and likely break even. Just a thought.

  • mikewrf18

Posted March 26, 2011 - 02:44 AM


You could sell your 426, buy a newer year 250f, and likely break even. Just a thought.

What he said. I'm sure somebody out there wants more power and you want less. I'd be willing to bet someone out there would be willing for a straight up trade. If you do decide to tackle a 250 swap, be sure and post pics. I find conversions very interesting. Good Luck.


Posted March 26, 2011 - 03:54 PM


A lot of work for very little gained in the process. I don't see what the benefit would be.

  • yz426fride

Posted March 28, 2011 - 11:52 AM


the 426 doesnt run, the entire motor top and bottom end are shot. i was thinking about the 250 motor because i found a cheap one, not the whole bike.

trust me if there was an easy way to get the 426 running i would be all over that.

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