wr400 engine swap


4 replies to this topic
  • gw1626

Posted January 11, 2011 - 11:45 AM

#1

i have a 1999 wr 400 yamaha. there is a 2002 yz 426 engine for sale by me. will they exchange with out to much modifcation? thanks for any info that will help.

  • rubbersdown

Posted January 11, 2011 - 11:50 AM

#2

Do not believe it will. If I remember correctly (correct me if im wrong here ppl) The 2000 and 2001 426 motor will swap right over (electronics and all) but the 2002 will not swap over because the swingarm pivot is a different size or something like that.

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  • mikesbaron

Posted January 11, 2011 - 03:47 PM

#3

Better answers probably in the YZ specific bike forum.

  • Birdy426

Posted January 11, 2011 - 06:02 PM

#4

Do not believe it will. If I remember correctly (correct me if im wrong here ppl) The 2000 and 2001 426 motor will swap right over (electronics and all) but the 2002 will not swap over because the swingarm pivot is a different size or something like that.


Thee has been some discussion on this before...or at least pputting a 2002 engine in a 2000/2001 frame. The '02 swing arm bolt is, in fact, larger than the 00/01s. I'm not sure how the 00/01 compares to the 400s. To use the 02 motor in the 99 frame, you would have to have some bushings machined up to bush the hole size in the center cases down to the same diameter as the 99 cases...shoulodn't be a big deal for a competent machine shop...

You would also want to take the carb from the 02 as it's a better carb (no cracking of the slide, and internal hot start), and just as an insurance, the CDI box...not sure if theree's any diffeence there or not, but I would expect there is.

If you can get it, you want the '02 exhaust, as well (at least the header) so you don't have to loosen the header to change the oil.

  • jsantapau

Posted January 12, 2011 - 05:07 PM

#5

Thee has been some discussion on this before...or at least pputting a 2002 engine in a 2000/2001 frame. The '02 swing arm bolt is, in fact, larger than the 00/01s. I'm not sure how the 00/01 compares to the 400s. To use the 02 motor in the 99 frame, you would have to have some bushings machined up to bush the hole size in the center cases down to the same diameter as the 99 cases...shoulodn't be a big deal for a competent machine shop...

.



those swingarm pivot bushings in the engine are a removable, and buyable part, http://www.starmotor...parts/home.aspx, part#23 it is possible to use a blind hole puller to sneak in behind them and pull them out but the safest, easiest bet is strip the engines down to the bare casings, heat them up, push them out with a press using appropiate press slugs as needed.




 
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