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WR trans in YZ250F

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I've been reading and searching all day, I've found every year under the sun except an '08. Has anyone done this swap on their YZ250F? I have an '08 YZ that I'm building for woods, thought the WR wide ratio would be nice. Anyone have input?

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I have a 2010 YZ250F thats running 2001 WR250F gears...direct swap.  Only item needed is the transmission gear set.  Other year WR will fit too 2000-2013.  I just liked the earlier years as they had a slightly higher top gear ratio. I use mine as a dual sport to run the LaB2V.  

 

And as far as your  most likely next question...a 2001, 2002 WR stator can be made to fit the bike  ( float ground, grounding of a CDI wire, and in some cases an older style ignition cover without the drain sight as the newer style interferes with the WR flywheel  , and a slight enlarging of the WR flywheel hole because the crank threads on a YZ are a larger diameter. ) .  

 

2003 up WR stator would require different cases and ignition cover. 

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Can you PM me your phone number so I can pic your brain a bit more?

And no stator swap. Have a battery LED bar for it and 2 LED lights for my helmet, light isn't an issue. Haha just want hearing to help it stretch its legs on desert races/rides, but I need nimble for woods/GNCC.

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I have a 2010 YZ250F thats running 2001 WR250F gears...direct swap.  Only item needed is the transmission gear set.  Other year WR will fit too 2000-2013.  I just liked the earlier years as they had a slightly higher top gear ratio. I use mine as a dual sport to run the LaB2V.  

 

And as far as your  most likely next question...a 2001, 2002 WR stator can be made to fit the bike  ( float ground, grounding of a CDI wire, and in some cases an older style ignition cover without the drain sight as the newer style interferes with the WR flywheel  , and a slight enlarging of the WR flywheel hole because the crank threads on a YZ are a larger diameter. ) .  

 

2003 up WR stator would require different cases and ignition cover. 

 

For this swap, do I use my YZF shafts and swap out gears only, or do I buy WR shafts and gears (thinking off eBay) and plop them in? I'm thinking I want to swap the whole gear box over to get as linear spacing as I can...

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In theory you can swap gears.... the shafts are the same. All use the same second gear since the shafts have second gear machined on.  You could create a custom tranny I guess use YZ first, WR rest or some other combo.  I have heard of one person using the YZ first. 

 

Anyway its probably easier and cheaper to source a complete gear set on ebay...its what I have done.

 

Just buy, inspect, drop in a complete gear set off Ebay.  

 

The hardest part is installing the gears and forks back in the case.  Take  your time it will work.  Your first attempt may leave you tossing a wrench.  I think it was the right side case...going from memory I think I put the gears in first, added the shift forks but spread out so they do not contact the drum,  then the drum halfway while pulling up on the gear shafts and rotating the forks into the drum slots then pushing in the fork shafts.  Even after 8 rebuilds I still have to think about the first attempt. 

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sky,

I've done the swap on an 03... no experience with the 08.

It's absolutely AWESOME.  Light weight , quick, AND fast.  After I did my swap, I had guys coming up to me and asking if it was 450.

If you do it, watch out on the 2nd to 3rd shift as it will literally jump forward due to the wider spacing of the gearing.  I had to watch out to keep from running into guys if I was too close.  And it makes it easier to carry the front wheel on that shift.

Good luck with it.

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For the sake of others who may refer back to this thread... Per my WR tranny comments I was sort of wrong with what I said.. 2nd gear is the same on all bikes but first gear is off of the shaft so you need the WR gears and the WR Pinion shaft (the shaft the clutch bolts to) .  Probably not an issue as most would buy a complete transmission off Ebay.. So if you wanted to do something odd like a YZ first gear and WR 2-5th you would retain the shafts , 2nd gear and just replace the 3rd - 5th gear sets.  I have not done this but should be possible. Nothing else is needed , all other YZ parts should bolt back together

 

The only weird install item I had during install was the aluminum cluitch rod ( Pencil looking part ) from my 2010 YZ was tight in the WR shaft.  I had to dremil polish the WR inner shaft bore some.  Might have just been manufacturing tolerances .....who knows.  Should have been interchangeable. 

 

Regarding Ger ratios ( From the Part manuals ) 

 

WR250f Trans 2001-2006  ( Widest Ratio Years )

5th 27/22 – 0.81

4th 24/25 – 1.04

3rd 21/28 – 1.33

2nd 16/28 – 1.75

1st 13/31 – 2.38

 

WR250F 2007 - 2013

5th 19/17 – 0.89

4th 21/23 – 1.09

3rd 17/23 – 1.35

2nd  16/28 – 1.75

1st 13/31 – 2.38

 

YZ250F 2001-2009

5th 24/25 – 1.04

4th 22/27 – 1.22

3rd 20/29 – 1.45

2nd 21/28 – 1.75

1st 14/30 – 2.14

 

YZ250f – 2010 - 2013

5th 24/25 – 1.04

4th 18/22 –1.22

3rd 18/26- 1.44

2nd 16/28 – 1.75

1st 14/30 – 2.38

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I have an 08 with a 2001 bottom end.  The higher top gear has it's obvious advantages.  The gap between 2nd and 3rd can be a nuisance in the tighter single track.  3rd gear is good for the fast stuff, but for the tight stuff it's a little tall and 2nd is just to low (13/51 final drive).  Makes me miss having a 6 speed transmission.

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Thanks for all the replies! I have all the parts and am working on getting a set of cams next. Motor is out of the bike and torn down so I can split the cases. My race bike quit on me last weekend so that will be fixed first. I should be back on the 250F project in a couple days though. 

 

Oh, i ordered a complete 2007 WR250F trans setup from eBay to do my swap. Need to inspect everything but it was complete with forks, shift cam, gears/shafts, etc.

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