Want to beef up the low end on a 2001 CR125

Discussion in '2-Stroke Discussion' started by oldguy, Mar 24, 2003.



  1. oldguy

    oldguy Always Broken

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    Last fall we talked to Eric Gorr about how to improve the low end response in thekids 2001CR125 cheaply. He suggested putting the exhaust manifold from a 2002 CR125 on. Well we finally got around to it yesterday and the results were great :yeehaw: . Thekid was testing it in the backyard and his first reation was look out holeshots.
    Totally cost after purchase and shipping from Service Honda $35 and about 30 minutes.


  2. Moto Squid

    Moto Squid Subscriber

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    hey old guy...is he going to be racing @ gravity again? What classes, I seem to be thinking it is 125jr but have a foggy memory. what about C?
  3. oldguy

    oldguy Always Broken

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    He will be in 125 Jr maybe a couple C's as well. Definately will be at Gravity it is his favorite track.
  4. enduroman

    enduroman Rookie DRN Member

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    Hey Old Guy,
    That sounds like a mod I could do to my son's 01 CR125. Would you have part numbers handy, so I could order it? Plus any tips on any problems you encountered when you installed it, would be appreciated. Thanks
  5. oldguy

    oldguy Always Broken

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    Enduroman
    Exhaust flange (joint,EX. PIPE) 18352-KZ4-L20
    Rubber exhaust ring (GASKET, EX. Joint) 18291-KZ4-700
    Metal seal (SEAL, EX. JOINT) 91304-KZ4-L11
    You could probably get by without the rubber o-ring and the metal seal but it isn't a bad idea for about $7 to get em.
    The flange is a bolt on (3 bolts) 5 minute fix. Pull the 2 springs off, remove the pipe from the cylinder, unbolt the old flange and then bolt on the new one. The flange is about 1/4 inch longer so once you replace the pipe and springs you will have to loosen the bolts where the pipe braces go to the frame- 2 spots (1 by the expanaion chamber and one right in front of the pipe/silencer joint.
    Total parts and shipping from service honda (DRN sponsor :thumb: ) $37.87
  6. Nevada Sixx

    Nevada Sixx Rookie DRN Member

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    i wonder if there is a mod lke that for the 01 cr 250?
  7. enduroman

    enduroman Rookie DRN Member

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    Thanks Old Guy! That is just the info I needed. Appreciate the help!
  8. CRrider125

    CRrider125 Rookie DRN Member

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    i just ordered the flange. i hope it's as good as you say it is.
    whats the difference? shape?size? or what?
  9. oldguy

    oldguy Always Broken

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    1/4 inch longer and has an obstructed lower quadrant
  10. trevor_zr600

    trevor_zr600 Rookie DRN Member

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    can comeone draw out what needs to be done to make one for my bike i have a lathe that i cna use and a milling machine so draw it out someone u say it has an obstructed lower quadrants wats thatdraw it please
  11. Moto Squid

    Moto Squid Subscriber

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    when you match the manifold to the cylinder the holes are not exactly the same (I think this is what you're talking about oldguy) , I've done just the opposite and put an 01 on my 02. All you got to do is take a dremel and do a little bit of grinding.
  12. oldguy

    oldguy Always Broken

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    Moto squid it matched up perfectly for us.
  13. motometal

    motometal Lifetime Sponsor

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    is that metal gasket a thin steel band? if so, you may try leaving it out and using black high temp silicone...it won't leak no matter what, and is cheaper
  14. oldguy

    oldguy Always Broken

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    Yes that is the thin metal gasket
  15. evworld

    evworld Rookie DRN Member

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    Will you be able to run pump gas with this mod.?? I run pump gas now.
  16. oldguy

    oldguy Always Broken

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    Yes it will not change the compression so whatever you run now will still work the same
  17. motoman542

    motoman542 Uhhh...

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    will that mod work on a 2000 cr125
  18. Racercr125r

    Racercr125r Rookie DRN Member

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    Yes the flange will work on the 2000 CR125. I have one along with a reed spacer. This 2 worked good together and helped out my bottom end a lot.
  19. evworld

    evworld Rookie DRN Member

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    I tried the mod today. It did beef up the bottom. But, my jetting is all messed up. I didn't have time to play with it other than the air screw. It helped some but not much. I was going riding so put the old stuff back on. What Jetting did you have to use. mine is 40pilot, 3clip, and 380main.
  20. CRrider125

    CRrider125 Rookie DRN Member

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    i just added the reed spacer and the new flange today and it made the bike feel like it had NO power! could it be my jetting or what? it acted like a 65



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