WR gear set in YZ

I want to install a WR 1st & 5th in my 2001 YZ250f.

I can not find anyone who has actually done it (parts numbers, tips, etc).

Even a call to a very polite but unhelpful Zy Ty racing went no where.

My local dealer, a . . . . not so much.

Anyone? Anyone? Anyone?

Gleen what you can from these two links here on the TT.

http://www.thumpertalk.com/forum/showthread.php?t=692203&highlight=transmission+swap

http://www.thumpertalk.com/forum/showthread.php?t=213476&highlight=transmission+swap

When I did my swap, I took the whole tranny over in tact, didn't want to mess with swapping out the individual gears and shafts. But there is much to be gained with that. My son likes a 50T rear and the YZ tranny, but that tops out early. WR 5th offers a higher top end speed. As I understand it, ratios YZ / WR 1st/2nd same, then things go different, but someone here may correct that. Changing final gearing with larger rear sprocket gets you back in the ballpark with the WR tranny. YZ 1st is tall, which is what I wanted to get away from, just too tall for the hills and rocks I sometimes do. I also noticed that the jump to 3rd is a little wide, so I'm looking at going either to a 12T front, or a 52T rear to bring that to less of a jump. If you've split the cases before, it no big deal to do. There are some links here on that, one very good by a young kid with pics and everything. From your handle, I'd say you are a chopper jocky. Thumbs up!

Thanks for data, and yes.

WR's have a lower 1st higher 5th. I do think 2nd is the same, but the gear spacing is a tad wider through out, so shifting from 4th to 5th if you just put a WR 1st and 5th in might be to far of a spacing

Gleen what you can from these two links here on the TT.

http://www.thumpertalk.com/forum/showthread.php?t=692203&highlight=transmission+swap

http://www.thumpertalk.com/forum/showthread.php?t=213476&highlight=transmission+swap

When I did my swap, I took the whole tranny over in tact, didn't want to mess with swapping out the individual gears and shafts. But there is much to be gained with that. My son likes a 50T rear and the YZ tranny, but that tops out early. WR 5th offers a higher top end speed. As I understand it, ratios YZ / WR 1st/2nd same, then things go different, but someone here may correct that. Changing final gearing with larger rear sprocket gets you back in the ballpark with the WR tranny. YZ 1st is tall, which is what I wanted to get away from, just too tall for the hills and rocks I sometimes do. I also noticed that the jump to 3rd is a little wide, so I'm looking at going either to a 12T front, or a 52T rear to bring that to less of a jump. If you've split the cases before, it no big deal to do. There are some links here on that, one very good by a young kid with pics and everything. From your handle, I'd say you are a chopper jocky. Thumbs up!

You can swap any of the gears in sets. Personally I would put the WR 4th and 5th gears in and the 08 yz piston. I did a swap on a 01 wr to a complete yz gear box, because I did not like the ratio for the tight woods in NJ.

Other than the pinion gear and wheel gear for each chosen gearset that I change when doing the swap what else should be changed? Did you guys put new bearings, washers, and circlips or just change the the gearsets?

From what I have read, you can't swap 1st because it is part of the mainshaft, but you can swap the others.

I'm going to go to a 50 tooth rear which will drop my overall ratio in 1st (and all other gears), then swap in 3rd, 4th and 5th from a WR.

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