Home Forums Tech Talk Stock Honda Cr125 Cylinder and piston?

This topic contains 9 replies, has 5 voices, and was last updated by  FREDDY SANDOVAL 4 years, 5 months ago.

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  • #37322


    Hi guys
    Just out of curiosity
    Where can I find a better price on a new 99 CR 125 Cylinder and a piston kit?
    It’s been a while from where I can remember how affordable those parts were.

    I’ve been looking everywhere, trying to replace my top end that the Nikasil got removed by my piston failure, and everywhere I’ve found so far is $390 for a new Jug, $125 for Piston kit, $ 85 bucks for the head, plus all gaskets.

    In all seriousness. Does anybody know of a more economical alternative? I wanna keep it legal for road racing in Laguna Seca.

    P.S. I should mention that my old cylinder already has the Power valve delete kit and blended.

  • #37327

    andy graham

    swedetech prepped cylinder @ fastech for around $470 less 10% for the Supernats sale makes that about the best deal I’ve seen…if you want just bare cylinder, no plugs, try partzilla.com for parts, I’ve ordered many times from them with no complaints…99 cylinder is $271.95 from them…that Fastech deal is the best, make sure you mention the 10% off supernats sale to get the discount…its posted at the top of his homepage

  • #37328

    Patrick Roth


    I have a DDR prepped cylinder kit which is less than a year old.  While it isn’t brand new I never had a failure and is definitely going to be cheaper than new.  If interested shoot me an email at proth0303@gmail.com.


  • #37334


    Thank you, guys for your input

    I will take both suggestions into consideration

    Thanks a lot.

    Oh! One more question, before I repair my engine, and keep from happening again.

    What would cause my piston to get melted on top, right at the exhaust port? Missing about 1/2 inch.

    I currently run a Pump Around carb, double pump system, 55 and 170 jets, 6 oz to the gallon pre mix. Etc.

  • #37335

    Mike Burrill

    Not sure if it is stock legal but you could send the cylinder out for replate.  I had Millennium Technologies fix a couple for me and they came out great.

    Mike Burrill -
    Karting Kartel

  • #37341

    Patrick Roth

    It sounds like you were too lean on the main jet.  What does the spark plug look like?


  • #37342

    andy graham

    you need to figure all that out before you spend a dime on parts…otherwise it’ll most likely happen again and you’ll have wasted your money

  • #37347


    Andy, Patrick, and Mike.
    All your input is greatly appreciated. And yes, I will totally figure out what went wrong before I go back together with new or used parts.

    Patrick, The spark plug looks dark grey inside the electrode, but the gap got bent with all the contact it made with pieces of ring and chunks of the piston.
    However it is grey in color, but not wet

  • #37397

    Michael LaGrone

    Your jetting will change depending on weather conditions, fuel and elevation.

    That being said with out providing a lot more detail in terms of the conditions. I run a 99 stock moto with a dual pump around system and a 170 main will only work at high elevation and a HOT day. Chances are that your main is to lean. I run a 175/55 as my starting point. I have stuck my motor before and it has always been related to a lean condition. Fatten it up… start with a 178/55 or for a new top end break in try a 185/55 make sure to get it up to temprature before hitting it. a little on the hot side is better that cold. Bring the temp up to at least 140 degrees then run it at about 125-130 degrees.

    look at this article



    #16 NCK Stock Moto


  • #37398


    Thank you, Michael
    That makes a lot of sense, especially when running Laguna Seca in January.
    It will still be cold out there, and there is some elevation as well.

    Very good info, Thank you.

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