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Yz 125

Discussion in 'MX/SX General' started by nitrofish, Mar 3, 2011.

  1. nitrofish

    nitrofish PR Addict

    Location:
    Nashport,Oh
    Unless the deal falls through I may be the proud owner of a 05 YZ 125! I know, a 125? It is what I was riding when I retired back in 90. 2 stroke screamer, pinned and clutch like he*#! I have been out of the big bike scene for 20 years, been learnin' the boy and pit biking. Any set-up tips or things to look for on this thing would be appreciated. Thanks in advance. MW
     
  2. MarctheSharc

    MarctheSharc PR Founding Father

    Awesome!.....more 125 pilots !!!!!
    The YZ's are pretty tough, as long as it doesn't looked beat on you should be good to go.

    I LOVE my YZ-144....!
     
  3. baxterj787

    baxterj787 PR Addict

    Location:
    Xenia, OH
    Good, solid bike. The 05s were new motor, new frame, and Y nailed it the first time out. About the only issue I have seen is once in a GREAT while the clutch lifter rod (that passes through the mainshaft of the engine) will crack. The culprit is usually traced to the two needle bearings that support the lifter arm in the LH centercase. I't an easy fix.

    Stock jetting was really good, too. Make sure the top end, fork seals and air filter are good, then ride it. I am rebuilding a 2003 model. I am looking forward to seeing and hearing more of these little bikes at the races.
     
  4. mxracer_0141

    mxracer_0141 PR Member

    Location:
    Grafton, OH
    Racing Number:
    141
    they are also notorious for cylinder head detination as well. mine runs like a raped date, but had problems with detination cuz of pump fuel. 100 or 110 octane usually takes care of it.
     
  5. sdjclevland

    sdjclevland PR Addict

    You have to replace the stopper lever or some call it the shift stopper that's behind the clutch basket. Those go bad they fixed it in 06 but the things have little bearings on them that come apart. This is a known issue forsure and when you order they new part you automatically get the updated part. You can replace it by just pulling the basket off but it's a pain in the ass and requires some muscling and prying. Or you can take apart that whole side and do it.
     
  6. sdjclevland

    sdjclevland PR Addict

    Just go on thumpertaLk and search "replace your shift stopper" and a giant thread will come up on it with some instruction and pictures
     
  7. TCracing

    TCracing PR Addict

    I got some Yz 250 Springs that will fit. That should help.
     
  8. nitrofish

    nitrofish PR Addict

    Location:
    Nashport,Oh
    Good info! I have done some searching myself. I am curious about upgrading to a 144. Is it best to buy a kit or bore, if you can use stock cylinder. What brands are best? Thanks. Matt.
     
  9. MarctheSharc

    MarctheSharc PR Founding Father

    I would get in touch with Eric Gorr at Forward Motion (630-825-5645) and send in the OEM Yamaha stuff.
    He will strip the cylinder, increase the bore, re-pate the cylinder, port the cylinder, cut the power valves, re-shape the head, give you a piston, ring, small bearing, and wrist pin. Just bolt it all together and go!
     
  10. hershey

    hershey PR Elite

    Location:
    Ozone Layer
    Racing Number:
    01
    This will only temporarily fix that problem. THe real problem is the inner clutch basket and pressure plate have worn past spec. The distance between the actuator rod ( in the LH case ) and the pressure plate has become to short and the excess pressure on that needle bearing causes premature failure. Just an FYI as I have repaired 3 bikes with this same problem.
     
  11. TwentyThreeMX

    TwentyThreeMX PR Founding Father

    Location:
    chesterland, oh
    i rode dmx153's 05 yz125 back when he got it and i loooooooved it!!!
     
  12. PitRacer

    PitRacer PR Founding Father

    Location:
    Medina, Ohio
    Oh yeah, 125's --- everyone's doing it!!!

    Here's my RM125 with 144cc Eric Gorr topend.

    [​IMG]
     
  13. Jon16

    Jon16 PR Founding Father

    Location:
    Canton, OH
    After I rode Sharc's bike, and mine went kaboom, I've actually looked around a little for a cheap yz 125. I can't believe I just said that.
     
  14. C Hudak

    C Hudak PR Addict

    Location:
    Lordstown, OH
    Racing Number:
    2
    I would have one in a heartbeat if I could get it to run like my 450!
     
  15. PitRacer

    PitRacer PR Founding Father

    Location:
    Medina, Ohio
    Here's some more 125 Porn that was posted at twostrokemotocross.com

    [​IMG]
     
  16. nitrofish

    nitrofish PR Addict

    Location:
    Nashport,Oh
    Nice Rm Pit, 89 RM 125 my last ride 21 years ago. I think this calls for a new thread. Post your glory days pics, 2 stroke in action or on the crate (yeah milk crate, remember when we had to build our stands) My problem is the pics are not digital, I will have to snail mail em. :)
     
  17. dmx153

    dmx153 PR Founding Father

    Location:
    Paris, Ohio, United States
    Racing Number:
    153
    I can't believe you said that either based on the last time I saw you on a YZ125.
     
  18. Windtunnel36

    Windtunnel36 PR Addict

    Location:
    Oberlin, Ohio
    We have a 98 YZ125 in the garage. It has been a fun bike to ride. We need a cylinder for it to get it up and going this year. My son railed on that thing. I would love to get it going.
     
  19. Jon16

    Jon16 PR Founding Father

    Location:
    Canton, OH
    Lol. Young and Dumb!
     

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