YZ / WR transmission ?

3 replies to this topic
  • JFisher304

Posted April 06, 2003 - 01:32 PM


How big a pain is it to swap the WR gearing into a YZ. I have a 98 YZ 400 that I have converted to a street legal motard. I do ride some long distance fairly high speed commutes on it, and to get the top speed I need at reasonable revs, I have it geraed so tall I have no bottom end at all. I rode a friends converted WR and it was much better. How much of the trans needs to be changed? Is it all different or can I change certain gears to make it work? Any help is greatly appreciated.


  • Hick

Posted April 06, 2003 - 05:34 PM


This swap has been done by a few members, but I'm not one of them.

I once read a post where a member found that you could not swap fifth gear only, the dogs would not mate with the YZ fourth, but you could just swap fourth and fifth.

On a 426 YZ fourth is w/in a few % of WR fourth. I think the 400s have the same ratios after second gear...

Anyway all you would need is the four gear wheels, some gaskets, and you should probably replace the snap rings and shim(s) on both shafts when you R&R everything. Maybe some new seals and gaskets would be in order as well.

Hope this helps.

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  • JFisher304

Posted April 07, 2003 - 11:33 AM


Ok, maybe I am reading wrong, but did you mean that the 4th and 5th gears in the wr and yz 400 are the same? If so, I assume that 1st and 2nd are lower in the wr. Maybe I can switch those around.......looks like I need to go look at a micro fiche and see what part #'s are different, then find someone that can figure out if they will all work together. I'll have to have someone do the work anyway, since I have neither the tools or experience to split cases.

  • David_Gronlund

Posted April 07, 2003 - 12:29 PM


Actually you can change just fifth, but I don't recommend it. I did my 98 YZ400 that way the first time and the jump from the stock YZ 4th to the new WR 5th was a big jump. So I cracked it again to find that you can't change 4th with out doing 3rd also because the dogs are different. So you have to change 3rd, 4th and 5th to do it the right way. Its not too hard, but you do need to know what you doing because you have to change out a odd number of gears because 3rd drives 5th, 2nd drives 4th etc... A good 4-stroke mechanic can do it no problem. My mechanic Ben at Bens Cycle Works in Mesa AZ has done it many times with success every time. Actually he helped me the second time I had it apart because it started getting confusing for me.


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