Yamaha yz250 wide-ratio gear set

Discussion in 'Yamaha' started by KDXfile, Nov 10, 2003.

  1. mtdirtbag

    mtdirtbag B level Member

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    And 2002; I have not done anything with newer but suspect that it maybe the same. If you have a good local parts man at Yamaha I think you could look at stock part numbers and get a good idea. I do have all the stock gears and shaft so if and when I update, even if I sold my 99 before hand I could tear down and match up to check for a difference. There maybe the possibility that one of the local shops may have a gear set around that you could match up with if you're willing to split the cases.

    Tom
     
  2. number9

    number9 C level Member

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    Just to clarify (on the image below) you ONLY purchased the items you listed and all the other components (washers, cirlips, etc...) were used from the 2000 YZ250 tranny, correct?

    What about #13 - AXLE, DRIVE - 5BE-17421-00-00? You purchased the #1 - AXLE, MAIN - 5BF-17411-00-00 for the 1999 WR400, but use the AXLE, DRIVE from the 2000 YZ250? I just want to be sure so I can order all the correct parts if I go through with this.


    [​IMG]

    Here are the items you have listed with the prices as per www.partsfish.com

    1 - Main Axle (shaft) 5BF-17411-00 $52.27
    14 - Gear, 1st Wheel 5BF-17211-00 $35.00
    23 - Gear, 2nd Wheel 5BF-17221-00 $32.90
    9 - Gear, 2nd Pinion 5BF-17121-00 $20.59
    19 - Gear, 3rd Wheel 5BF-17231-00 $28.19
    6 - Gear,3rd Pinion 5BF-17131-00 $36.14
    21 - Gear. 4th Wheel 5BF-17241-00 $32.63
    7 - Gear, 4th Pinion 5BF-17141-00 $44.99
    15 - Gear, 5th Wheel 5BF-17251-00 $30.61
    3 - Gear, 5th Pinion 5BF-17151-00 $26.62
    TOTAL (from Partsfish) $339.94
     
    Last edited by a moderator: Nov 17, 2003
  3. KDXfile

    KDXfile C level Member
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    It's my understanding that since 1st pinion gear is on the main axle shaft; that one is required. The other drive axle can be used from the old setup.
     
  4. number9

    number9 C level Member

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    What year & make was the donor bike for this - WR426? Do you know if the WR426 1st gear is lower than the YZ250 1st? Is 2nd, 3rd the same on both bikes?

    Thanks.
     
  5. mtdirtbag

    mtdirtbag B level Member

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    Actually the answer is above; the gear set we used is from the 99 WR400 and your 2000 model is one of the bikes that received the switch. It could be that the WR426 may work, but I would be wary of heavier gears that may cause some clearance problems. Actually we have not had any problems with the trannys in any of these bikes and can't even guess how many racing and trail riding miles we have on them.

    Tom
     
  6. number9

    number9 C level Member

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    I'm sorry Tom, the last question was actually for Squid Racing concerning his friends' 2003 YZ250 in the picture. I was thinking of maybe selling my bike and getting an 03-04 and then perform the WR conversion on it.

    BUT- I do have a question for you TOM - does the 1999 WR400 gearset have a lower 1st than the 2000 YZ250, or is it just a taller 4th & 5th with 2nd $ 3rd being the same, or are all the gears slightly different ratio?
     
  7. mtdirtbag

    mtdirtbag B level Member

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    1st is a little lower and if this ole memory is working correctly there was a little difference in each. Actually the spread is great for the type of riding we do and I don't notice a problem the few times I motocross. In fact the gearing seems to be tailored for the bike.

    By the way, thanks for posting the prices on the gear set; we purchased two YZ's in Canada in 1999 for $4300US a piece and he cut us a screaming deal on the gears at $350 per set(looks like he made up for some of the purchase price on the bikes!!) That same year we had purchased a YZ from another dealer for $3800 for one of my sons but that dealer couldn't get any more that year.
     
  8. YZ Abuser

    YZ Abuser C level Member

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    I looked up the info I had posted over on ThumperTalk, click HERE to go there.

    I'll try sum it up here and if you have questions jump over to TT for the whole thread.

    This info was for my '99 YZ250. The gear ratios on new bikes might have changed slightly so check your manual. I believe all the WR gears are still the same.

    ---------------------------------------------

    I have a '99 YZ250 that I was considering making a wide ratio. I know the '99 YZ 250 uses the same trans as the YZ 400. I wanted to see what gears would be required to make mine a WR. The WR426 gears are the same as WR400.

    The info I'm using came out of Chapter 2 General Specifications. My YZ ratios are as follows:

    1st 27/14 (1.929)
    2nd 25/16 (1.563)
    3rd 23/18 (1.278)
    4th 24/22 (1.091)
    5th 20/21 (0.952)

    99WR400F
    1st 29/12(2.416)
    2nd 26/15(1.733)
    3rd 21/16(1.312)
    4th 21/20(1.050)
    5th 21/25(0.840)

    You'll notice 3rd is pretty close. After looking at this a little closer I figured I could get by with adding only the 4th and 5th gear sets. This would make the 3-4 jump slightly taller. Wider than the YZ 3-4 gap, but smaller than the WR 3-4 gap. The YZ/WR 3-4 gap is roughly half (54.6%) the jump of the WR 3-4 gap. The 4-5 gap would obviously be the same as the WR.

    The next bit is from someone smarter than me that figured out the percentage of change between gears.

    "Starting w/ first to second jump here is what your smoker 250 would be like:

    Stock
    19%
    18%
    15%
    13%

    W/ WR 4th & 5th :
    19%
    18%
    18%
    20%

    You would be almost 12% taller in fifth, keep in mind if you go from 14/49 overall to 14/51, for example, you take back 4% of that."

    My reason, besides money, for only wanting to change 4th and 5th is because I don't need the super low 1st and 2nd gears. I was going to put a 52T rear sprocket on which is two more than stock. That would lower 1st and second gears while still giving me a significant increase in top speed.

    I know it's late, but I hope that helps out some.
     
    Last edited by a moderator: Nov 27, 2003
  9. number9

    number9 C level Member

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    Thank you for the info and link.
     
  10. YZ Abuser

    YZ Abuser C level Member

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    Number9

    I edited it to read better and added that the WR426 gears are the same as the WR400 gears. Let me know if you make the swap.
     
    Last edited by a moderator: Nov 27, 2003
  11. number9

    number9 C level Member

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    Sweet - I didn't know the WR400 & 426 gearsets were the same. That is nice to know. Maybe if I do this I will just do 4th & 5th as well. It would be nice to do the entire tranny though.
     
  12. YZ Abuser

    YZ Abuser C level Member

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    N9

    I would double check the part numbers just to make sure. This is waht I was told and I believe it's true. You can go to Yamaha's website parts&service/parts catalog and get all the part numbers.

    If you really need a low first and second gear then you may want to go with the complete tranny. If you add a couple teeth to the rear plus the low first that makes 1st useless to me in most situations.

    Take care and let us know how it goes.
     
  13. number9

    number9 C level Member

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    This post - along with my brother getting a new bike - has renewed my intrest in riding again. I have all but decided to sell my bike come spring and get an '04 YZ250 and most likely perform the WR conversion on it.

    Maybe I won't put so many miles on the R6 next summer........ :D
     
  14. mtdirtbag

    mtdirtbag B level Member

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    I thought I would resurrect this post as I purchased a 2004 YZ250 and knew that a lot of legwork was done for parts and numbers. I just want to thank all of you for that work and will start chasing down numbers and comparing to what my 99 has in it. The one interesting thing I found in this thread that I had forgotten was that the WR400 & 426 gear set is the same; I guess that explains some of the problems that the 426 experienced when raced. I will probably ride it the way it is for a little while and spread the spending out to keep peace in the family but will let you know how and when I make the changes. A lot of the work was done on the bike with suspension, tank, triple clamp, bars & damper so right now I'm adding an 11oz FWW and my own preference in tires. I am looking for different spring weights for both forks and shock; I need .41kg's for the forks and 4.8kg for the rear. Right now it has .45kg in the fork and I have to call Factory Connection and get the rear shock spring weight. If anyone is looking to re-spring their 04 at a higher rate, keep me in mind.

    I just had my first ride of the year and first on the new bike last weekend just accross the border in Canada. We put in about six hours with breaks for tire repairs (2) and to put together one of those Orange bikes after a close encounter with a tree. Some of the trails are pretty whooped out but I was really impressed with the suspension even though it is set-up for a 220+ rider. The only thing I had trouble with was it kicking up in the rear over six inch logs at speed, but adjusting the clickers helped somewhat with that. We're camping up there this weekend so I will have more time to fool with it, but I'm very happy with it overall.

    Happy trails, Tom
     
  15. dog2

    dog2 C level Member

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    I am not sure if the gear swap works on 2003 or newer bikes. I have compared the transmission shaft P/N's on the yamaha website, and it looks like the WR426 and YZ250 share the same shafts in 2002, but different part numbers are called out in 2003 and 2004. Has anyone actually done this on a newer bike?
     
  16. Ralph Wiggum

    Ralph Wiggum C level Member

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    the silencer on that bike looks like a lizard
     
  17. cactusreid

    cactusreid C level Member

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    WR250-2 stroke-YEAH those were GREAT xcountry bikes!I had the pleasure of owning 2 of them a 92 and a 96.If I had not stumbled on to my 01 EC 300 GasGas i'm sure that I would still be riding my 96!
     
  18. number9

    number9 C level Member

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    ^SQUID^ Racing's post on the first page says he has a friend with an 03 W-R tranny using the WR gears. Maybe he can get some detailed info (part#'s) from him to post here.
     
  19. speed3172

    speed3172 C level Member

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    I thought it might be time to re-resurect this post. From what I read, it seems that the swap worked on a 2003 (and I presume a 2004) YZ . I'm thinking of building up an '05 YZ 250 (2-stroke) woods bike.....if the gear swap is possible on this bike, things could be very interesting. Anyone have any idea what I need to compare from a part number standpoint to confirm this would work on the '05 model as well?
     
    Last edited by a moderator: Dec 6, 2004
  20. Bandit9

    Bandit9 C level Member

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    I would call Ty Davis's shop and ask him. He would know. I know he has put the WR tranny in a YZF, so I would think he would know more about this than anyone.
     

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