WR 5th gear into '03 YZ 250.......

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#1
I took the time last week to install 5th gear from the 2001 WR 426 into my '03 YZ 250. I like my 13/50 gearing for the tight technical stuff we ride, but I hated the low 5th gear ratio that resulted, so I bought the 5th wheel and pinion gears for a WR 426 and installed them in my 2 stroke, resulting in a 12% higher 5th gear for fast sections and connector roads. Now my first 4 gears are nice and close for the trail sections, and I've got overdrive to cruise the fast stuff..........
 
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#2
Mainjet said:
I took the time last week to install 5th gear from the 2001 WR 426 into my '03 YZ 250. I like my 13/50 gearing for the tight technical stuff we ride, but I hated the low 5th gear ratio that resulted, so I bought the 5th wheel and pinion gears for a WR 426 and installed them in my 2 stroke, resulting in a 12% higher 5th gear for fast sections and connector roads. Now my first 4 gears are nice and close for the trail sections, and I've got overdrive to cruise the fast stuff..........
Very nice! I run 15 48 in mine, but a higher 5th would be awsome in the desert. Is the 01 wr the only one that fits in the 03 YZ250?
 
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#3
5th Gear

dcwilson said:
Very nice! I run 15 48 in mine, but a higher 5th would be awsome in the desert. Is the 01 wr the only one that fits in the 03 YZ250?
There are several years that run the same part numbers. If you want to relieve the case a bit (For 1st gear) you can run the entire WR transmission. Look up on the parts fisch, on the Yamaha web site, and use the shaft part numbers as your key. As long as the shaft number corresponds to your 2 stroke.....it will work.
 
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#4
Mainjet said:
There are several years that run the same part numbers. If you want to relieve the case a bit (For 1st gear) you can run the entire WR transmission. Look up on the parts fisch, on the Yamaha web site, and use the shaft part numbers as your key. As long as the shaft number corresponds to your 2 stroke.....it will work.
Sweet, thanks. I like the 5th gear overdrive idea, like you did. Too bad I didn't know about it a couple of weeks ago when I had my bottom end redone. I thought it would be some tricky mod, so I didn't even ask.
 

fuzzy

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#5
If you want to relieve the case a bit (For 1st gear) you can run the entire WR transmission
THIS is good news!! I've heard of some tricks for performing this, but they intailed narrowing of all the gears w/ a lathe. This sounds much better. Maybe a new WR250 2-stroke is in my future!! :)