Home Forums Shifter Karts Shifter Motor Project

This topic contains 13 replies, has 8 voices, and was last updated by  Ben Lewis 5 months, 3 weeks ago.

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    Gary Atkinson

    Hey guys!!

    I want to build a shifter motor from purchasing a motor or bike. I have seen a website ( http://metal-matrix.com/stockmoto/ ) that compares the years of different motors and what may need to be done to make the stock moto. I do not race competitively, I am the weekend warrior that wants to do this on a budget but yet be somewhat competitive on the track.

    I ma looking for some advice from you guys so i can learn from your mistakes or from your expertise.

    I have been karting for about 3 years. I run a PRD on a CRG RR.




    Chris Reinhardt

    Don’t waste your time building a “bike” motor, either buy a new kit or buy a used complete setup…

    If you do a bike motor, you’ll need a 97 or back CR125 for the 6 speed, or use a newer donor and find a 6 speed on ebay and pray no gears are bad…

    A decent ignition would be a 99 and up with the same year box, then you’ll need a carb setup and fuel system, pipe and pipe mount, motor mount, and J shifter….

    It’s way cheaper to buy a used motor setup for a kart and bolt it on….

    Good luck….


    James McMahon

    Gary what’s your budget? A CR125 stock honda “kit” might be the best way to go for what you are planning.  Like Chris said taking a motor off a bike can be a can of worms. A “good” motoX motor can come to pieces pretty quick when you put it under the stresses of a kart leaving your with time and money down the tubes.

    If it’s for fun, hell skip the CR125 and just go to a CR250, it wont be much (if at all) faster than a CR125 but it will be TONS of fun and the damn thing will lug forever. Shark Shifter have all the parts you might need for either of these projects.


    Gary Atkinson

    Chris and James,

    First off, thanks for replying and giving me your opinions.

    I really want to keep this project as low cost as I can.

    I have found a 97 cr125 for $500. I’ve yet to see it but from talking to the guy he says it runs good. Of course looking at it closer will determine if it’s really that good.

    I should’ve said in my initial post that I’m not afraid and enjoy tearing things down and building back up. So this project is something I would enjoy. Plus I get a good grip on the workings of the cr125.

    I really want opinions on what year to buy. What other parts I need to purchase in order to complete it as a kart motor.



    Chris Reinhardt

    You’ll find out quickly, you will have to tear it down, and you will most likely replace the jug and crank at least plus the main bearings, gaskets and seals….  You’ll be very quickly north of $500 in parts, and that’s if the cases are any good, the clutch basket, inner hub, and clutches aren’t wasted…

    I love when people ask for advice and don’t take it… :)

    Good Luck….


    Finch Guenther

    If your looking for a project then my opinion would to be what James suggested and by the motor in kit form. The kit comes from Honda in a box of 340+ parts. Again this is just my opinion.


    Gary Atkinson


    I hope you don’t think I’m disrespecting you. I’m just trying to figure out a couple of avenues to go with this project.

    I totally understand that by buying a motorcycle that I’d have to completely tear it down. I was planning on it. I look at prices online for just motors, not all the other accessories and it’s upward of  $3000 and if I want the swedetech its $4000. I am simply trying to get on the track with a shifter for much cheaper than that.

    Im patient, I will hunt for a deal. That’s how I got my first kart.

    I just wanted to know what everyone’s opinion was. Maybe that’s where I went wrong. I said advice. Lol. My bad :p


    thanks for the reply. The kit sounds fun.  I will have to check it out.


    Frank Rapisarda

    Hey Gary if that 97 runs half way good, and you just want to have fun grab it. Then give Mike @ shark shifter a call for all the mounts you will need, get a good used pipe and a carb and fuel system,then drive it till it blows. Then take the winter to rebuild it. I got an 01 off ebay this past winter and rebuilt it completely for about mid to high 600’s


    Ray Lovestead

    Gary I’ve done exactly what you are talking about.  Don’t be discouraged.  Given enough time you can overcome any issues.  I bought a 1999 CR125 bike off craigslist for $800 bucks.  I tore the motor out of it, kicked the rest to the curb, tore down the motor, replaced the bottom end and top end and it worked perfectly for me.

    Then I went ahead and replaced the 5 speed gearbox with a used 97 gearbox from ebay.  $300 bucks.

    Fact of the matter is, Honda parts cheap and widely available.  Also, new parts or old, they will break and wear out on a kart.  Karts are very hard on parts, and unless you have loads of money to pay someone else, you will become an expert at fixing the motor yourself.



    Chris Reinhardt

    Gary, no offense taken…  You’ve been karting for 3 years, I’ve been building these motors for 30 years!!!!


    Read your PM…



    mal crosher

    Hi Gary.
    Personally , if you happen to be around 5 ‘ 8 tall and 130 lbs . The 80/85 cc kick for type of karting you looking at.

    Parts cheaper again. Way lighter and compact , gears closer together , rev higher and just more forgiving all around.
    Front brakes and medium tyre like maxis hg3 and you can’t go wrong.


    Ben Lewis

    I may be a bit late to this thread but I recently have done this conversion. The engine i got was already attached to a kart but was very much in dirt bike form with little done to it but bolted in. I decided to take it in a stock moto direction (even though it’s a 96 and wouldn’t be allowed). Here are some basic things you’ll need to consider doing:

    1)Rebuild everything!!! Top end and bottom. This will save you headaches. Trust me on this I thought I could just do the top end because the play in the crank was within tolerance and BOOM shrapnel from the bottom end going bad ruined my day and added $500 to my budget. Then I had to rebuild anyways.

    2) Remove the power valve and put some blended plugs in. Not only will this give you better Kart specific power up top but will keep the power valve cover from wearing through your nice exhaust since the stock one will be removed.

    2) Plug up the hole in the case you just created removing  the power valve with a unit that Fastech will sell you. Use  a little RTV around the collar even though it rests on a seal anyways

    3) Remove kick starter and plug it with another billet seal

    4) Find a place to mount the coil I did mine off the case with a little swedetech unit

    5) Buy a pipe and mount. Ive got the ‘old’ RCE its sweet

    6) Get an o-ringed exhaust manifold. They are well worth it.

    7) If your going to do the weekend warrior thing get a wiseco piston kit they have 2 little holes that lubricate the rib to help w/ sticking

    8) Get a side cover for the stator side (swedetech)

    9) Run a y-hose or do what I did and block off one of the water outlets on the head.

    10) Run a water temp sensor. Trail tech sells an awesome little unit.

    11) Decide if you want to run a UNI filter or a box. Personally I run a UNI

    12) Buy a PWK/M carb and run a pump around or figure out a fueling setup. Look up Tiger Racing’s Poor mans pump around. I use a pressure regulator and a return in this fashion. It would never race but works pretty good for track days.

    Lastly you’ve got to have a proper chassis/mount to put it on and all that comes with that. All these steps have little details that really add up. I would estimate that without learning mistakes I’m in at about $800 for the conversion after the $500 motor. With mistakes and its approaching 2K all together. A savings sure but whats your time worth? It can be a lot of work but personally I like a little pain with my enjoyment. Yes you will get very familiar with tearing down the CR, and in relative terms it’s quite easy and cheap to work on. This is why I chose this setup because its way more involved and you can do the work.  But, you gotta like that sort of thing or it will drive you mad!!  I wish you luck and post pics when you’re done



    Ben Lewis


    Ben Lewis

    Here’s some pics for motivation

    This is what you don’t want

    Here’s the (almost) final product


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