Home Forums 2-Cycle Racing Good guide for 13 year old to rebuild KT100?

This topic contains 2 replies, has 3 voices, and was last updated by  Walt Gifford 3 years ago.

  • Author
  • #50535

    Ron Horwitz

    I bought a used kart with an unknown KT100 on it, and it has been better than we deserved it to be.  We’ve put 20-30 hours on it ( he used to run 13500 rpm and has become more comfortable to where he is now 14600 rpm) with my son learning the ropes during open track test days with one carb rebuild and nary a hiccup.  Like I said, better than a totally unknown engine should have been.

    I am going to buy a pro-built engine as our primary, but I would like my son (13 years old) to rebuild the old one to introduce him to the mechanical side and give him the satisfaction of seeing his own creation run, even if it is slightly down on power and a spare for us.

    Can anyone recommend a good step by step guide for him?  Looking for something written clear enough (with pictures or suggestions for YouTube videos) that he can do most of it himself.  I’ll help with the precise measuring, but I would really like for him to own this project.

    Thank you!


  • #50543

    Jay Sinon

    The book by Gene Genibrel The complete Yamaha KT100 was a very good book you can also get all the specs. online by going to Yamaha and downloading the owner manuals. You can do a lot yourself but you will need someone to spilt the crank so that the rod can be installed  Splitting and pressing the crank is probably to much for a 13 year old not to mention having the right tools to do the job correctly. The rest of it is straight forward however just a word to the wise you probably want to by your wife a new toaster oven after heating the cases to get the bearings to drop out or your food will taste funny for a while.

    Good Luck!

    TaG Sr.

  • #50552

    Walt Gifford

    The book http://www.amazon.com/Racing-Yamaha-Kt100-S-Engine-Genibrel/dp/093683451X is what got me started but, you can’t just rebuild the engine with simple hand tools. You need so much stuff that you’ll be in the rebuilding business by the time you’re done. I made allot of the tools myself but I have a machine shop. A 13 year old should have no problem doing a full blueprint if he knows basic shop safety and has experience working on lawn mowers and such but there is a big investment in tooling at the start.


    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

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