1998 WR400F questions (Updating/EFI)

4 replies to this topic
  • mitsudriver274

Posted December 16, 2012 - 07:56 PM


I am fairly new to dirtbikes as this is my first, but this is defintely not my first bike. This will be my third motorcycle build and I am quite excited.

A few questions:

I'm trying to update the look of the bike a little and would like to know the newest plastics that will fit. From my understanding 2003 wr426 plastics and tank will fit the bike and give it better ergo. I would like to replace the fan shrouds fork covers, evertying, the stock plastics are pretty beat up.

I'm assuming this bike has never been properly maintained as I do with everything I purchase so i'm going to do the timing chain, is there anything else that should be replaced along with it? In car engines you usually replace the timing chain guides but in this case the guides cost $150 so if I can get around it I'd like to but i'll see what they look like once I get it apart.

A question regarding the new 2012-2013 wr450f, does anyone know how the efi system senses cam/crank position? No more carburators for me, I rather have an excel spreadsheet over jet changes.

  • MANIAC998

Posted December 17, 2012 - 06:13 AM


Yes, the cam chain should be replaced, but there has never been a need to replace the guides that I've ever heard about. And I've been on the fourstroke Yamaha's since '98. As far as prefering EFI over carbs, to each there own. I live out here in Montana, so the temp/elevation changes quite dramatically, and while I change the jetting, most of my friends don't, and never have issues. Fourstrokes are bathed in oil, so they will run on any kind of lean jetting without siezing.

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  • mitsudriver274

Posted December 18, 2012 - 10:31 PM


Any have any experience with what plastics will fit the bike? I'd like to do the newer 03 yz tank and seat for better ego

  • MANIAC998

Posted December 19, 2012 - 04:15 AM


I have no idea if '03 will fit or not. I do know that you can switch over to the YZ plastics/tank/seat of the same year to get better ergo's.

  • Birdy426

Posted December 20, 2012 - 10:25 PM


The 03 to (I think) 07 plastics will work...subframe, airbox, side panels and fender out back (gotta do it all together...can't use 03 and newer side panels on 02 and older subframe and airbox), tank and shrouds up front. You have to build a couple of brackets to mount the tank. Nothing too dificult. Search this forum and you can find a thread with the pattern for the brackets.


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