2000 YZ426F to WR Gears???


11 replies to this topic
  • Ricks426

Posted September 10, 2011 - 05:05 PM

#1

I have read the old posts, but got all confused with all the years talked about. Anyway, split my 2000 YZ426F cases today and the second set of gears on both shafts are missing half of there teeth. All other gears look to be alright. If I need all new gear sets anyway, I was wondering if I could just put the WR gears in with spending about the same amount of money. Is this possible? Could I use the same shift forks and other parts? Can single gears be changed or does the whole shaft have to be swapped? I ride more trail than mx, will I be happier with the wr trans, or will I lose that wheel lifting torque of my YZ?

  • upthemaiden

Posted September 10, 2011 - 07:01 PM

#2

I'd love to know this as well. My yz426 is a street tard and I've noticed my gears are way too close together. I'd really like to swap in the wr gears so the RPMs would actually drop a little when I shifted.

As far as losing that wheel lifting torque, I feel like it would be the opposite. With the wr setup you could gear the bike lower and be able to keep the same top speed but lower the ratio on the first few gears. I don't ride off road but riding the wr gearing on the street would let me lower my cruising rpms at the same time as dropping my ration in the first few gears. More wheelies AND more comfortable cruising. Doesn't get any better!

Ooh, and by the way, if you really want to do some research yourself, browse the fiche on here or on bikebandit and compare the part numbers. You'll know exactly which parts are different and which are the same.

  • grayracer513

Posted September 11, 2011 - 11:19 AM

#3

The WR gear set from '98-'02 will fit your 426. The output shaft and shift forks can be reused, but the main shaft has to be changed out since it has the first gear pinion cut directly on it.

  • Ricks426

Posted September 11, 2011 - 02:07 PM

#4

So I can just change the 2 broken gears and button it back up? Does anyone know where I can find gears at the best price?

  • grayracer513

Posted September 11, 2011 - 03:26 PM

#5

You can if the two broken ones are the only problem. Check everything carefully. If you only plan on replacing the damaged parts, you need to stick with the YZ replacements, though. You can't use just one ratio set from a different trans without creating a weird spacing gap in the trans as you go through the gears.

  • Ricks426

Posted September 11, 2011 - 05:01 PM

#6

Yes, Now that I know that I can just change the 2 broken ones, I'll probably stick with the stock gearing, but if I can find a used shaft from a wr, I'll change it up. As long as I can keep the cost down. I just want to get it back together so I can ride again before the snow flies, and maybe even get the studded tires back on for the ice. it's been down for over a month and my little '73 honda 50 with a 125 engine in it just isn't cutting it! thanks for your help

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  • upthemaiden

Posted September 12, 2011 - 04:00 AM

#7

I just want to get it back together so I can ride again before the snow flies,


Story of my life!

Make sure you post up if you find a good price on the wr gears and take some pictures if you do the swap so I know what I'm getting into. I have to rebuild my bottom end eventually anyway and I'd love to put the WR gearing in there while I have it apart.

  • pscook

Posted September 12, 2011 - 06:52 AM

#8

I dropped a wr400 transmission into my 426, no issues. Like Gray mentioned, don't arbitrarily swap ratios without looking at the gaps between gear sets. I have a complete YZ426 transmission if you are interested, the only problem is fifth gear slips. PM me if you are interested.

I have also read that possibly WR450 gears will fit the 400/426 cases, but I am not completely positive on that. And, it is possible that YZ/WR250 (two and four stroke) gears may fit on the shafts, but that may be looking too far outside of the box, so to speak.

  • grayracer513

Posted September 12, 2011 - 07:24 AM

#9

I have also read that possibly WR450 gears will fit the 400/426 cases,

They won't.

it is possible that YZ/WR250 (two and four stroke) gears may fit on the shafts,

The 250F is too small/light for the application. YZ250 gears are similar, but different, and don't mix in well.

The correct new replacement parts are not terribly expensive. The best bang for the buck is just to buy what you need new.

  • pscook

Posted September 12, 2011 - 07:56 AM

#10

They won't.

The 250F is too small/light for the application. YZ250 gears are similar, but different, and don't mix in well.

The correct new replacement parts are not terribly expensive. The best bang for the buck is just to buy what you need new.


I was checking out the threads in the two stroke section where some people mentioned swapping 450 gears into a 250 two-stroke, so I figured what's good for the goose is good for the gander.

Interesting reading here...
and here.

Not saying it's a great idea, but it might be an interesting experiment.

  • Ricks426

Posted September 12, 2011 - 08:36 AM

#11

I found the best price on gears at Cheap Cycle Parts, the 2 I need are about $50 a piece. I'm just going to stick with the yz gearing, can't find a used wr gear set anywhere.....probably from all the guys looking for them.

  • grayracer513

Posted September 12, 2011 - 08:39 AM

#12

Interesting reading

Neither of those links definitively state that the complete 450 trans fits a YZ250. In fact, the one featuring the YZ with the WR trans in it states that the used of the complete trans was "more work". The upper three gears, according to the write up there, apparently do, but I'm not completely certain of it.

This is what I do know for certain:

  • There are 3 generations of YZ/WR 450 ('03-'05, '06-'09, and '10+), the 400's and the 426's. There are two WR450's ('03-'06, and '07+)
  • The YZ400 and WR400 trans was based on the YZ250, and the two will interchange freely.
  • The 426 and the 400 have fundamentally identical gearboxes.
  • The Gen1 450 was a four speed. The Gen1 WR450 5 speed will bolt directly into the the Gen1 YZ450, but requires the whole, complete trans including both shafts, shift cam, and forks.
  • I know of one Gen1 YZ450 that had the close ratio YZ426/400 trans installed, but it was described by the TT member who did it as a "PITA", and involved custom machine work. This tells me that the 426 trans does not directly fit a Gen1 450. Because the Gen1 will directly accept a Gen1 WR450 trans, but not the 426 trans, I don't see how one could expect the WR450 trans to directly fit the 250/400/426.
  • Gen1 450 transmissions are about 12mm narrower than the Gen2 gearboxes, and the two can't be interchanged.
  • Gen2 YZ450 and WR450 transmissions are freely interchangeable, in whole or part.
  • Gen2 and Gen3 YZ450 transmissions are the same other than one updated gear pair.

The easiest thing to do if you want WR gearing in a 400 or 426 is to use the WR400/426 parts.





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