yz125 stock gearing

Discussion in '2-Stroke Discussion' started by CRrider125, Mar 31, 2003.

  1. CRrider125

    CRrider125 Rookie DRN Member

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    What is the stock sprocket sizes for the 2002 yz125?


  2. MRKRacing125

    MRKRacing125 Rookie DRN Member

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    The rear I believe is a 48, I went to a 51 and regret it on wide open tracks. I find myself shifting alot more than I should, but I kill everyone in corners with jumps right out of them. The front I think might be either a 12 or a 13 ratio. Mine is a 13. If you want somemore low end go with a 49 or 50, preferable a 49. I have good things about them. Hope this helps you out.
  3. 96717

    96717 Rookie DRN Member

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    i have an 01 and the stock gearing is 13/48 im pretty sure yours is the same.
  4. atc3434`

    atc3434` Subscriber

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    Yeah, my '01 was a 13/48 as well. Too much gear! Thing would do an honest 70mph. Went to a 51 in back... still has plenty of topend, but it works nice in the woods now!
  5. Combat767

    Combat767 It's all about the dirt..

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    Stock sprocket ratios are 13/49. They actually added a tooth to the rear from 01 to 02. I rode my bike stock thinking the magazines can't be correct about gearing the bike down. I rode the bike and it really fell off the pipe going up hills in third gear. That's an eery feeling when you're trying get speed to get over a jump! I decided to add two teeth and purchased a 51 tooth rear sprocket. The bike actually feels great now, but I do have to shift alot more. The only other addition to my YZ is a set of V-Force reed valves. They made the power snappier, but I don't know if it's $120 worth of snappiness. I'm currently looking into putting a 144cc Eric Gore big bore kit in my bike. I'm hoping to take off at least one tooth if not both and go back to stock gearing. I'll have to experiment a little but one tooth should spread the gearing out enough and leave plenty of power on tap everywhere. I hope this is of some help! :)
    Last edited: Apr 2, 2003



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