Turn a YZ426 into a WR426

Gear down first

Thats funny, you want to slow yours down, and I want to speed mine up!
I would play with the gearing before I did anything else. Try going down on the rear a few teeth, or going up a tooth on the cs. You'll get longer gearing for the tight stuff. Ive never heard of anyone changing the timing from the YZ to WR, but dont think I would bother. Although thats possible, you would probably not like the change. There are lots of ways to de-tune a bike, just ask Yamaha what they did to the WR's!
;)

WR gearing

Somebody on the YZ426 board (thumpertalk.com) posted about inserting WR gearing into a YZ. If I remember correctly, he swapped the 1st,2nd, and 5th clusters. Anyway, you can go there and use the search function to find the thread