Home Forums 250 Superkarts General Superkart questions

This topic contains 6 replies, has 4 voices, and was last updated by  Mark Traylor 9 months, 2 weeks ago.

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  • #61101

    Ben Lewis
    Participant

    Hi all,

    First, I apologize if these questions have been covered elsewhere or if I’m being naïve. I’ve been into sprint karts (stock moto) for the a few years and am starting to think about super karts. I tried an ICC and its great but didn’t seem like that big a step esp for the money. (This is how you know you have a problem with speed when ICC doesn’t fill your needs) There’s a lot of info out there but I have a few lingering questions.

     

    1) Why is no one using the cr500 in their superkart? (or kx500 for that matter)

    They are relatively available, cheap, supported by Oval racing, and can make good power. Is it a Stroke X Bore thing? I’ve seen these thing revved to death on an oval for 20 min straight so I don’t think rpm is an issue as far as I can tell. It would seem power wise the cr500 would fit neatly in between the 250 single and 250 double.

    2) What is the difference/advantage between the GasGas 250 and the Cr250?

    I would most likely be getting in at the 250 single level with the cr250. I’m running a cr125 right now and I have a cr250 (bike) as well so for me the cr250 seems like a good choice because it’s very familiar and I would be building my own motor. But the GasGas seems to be trick piece. Educate me please.

    3) An obvious focal difference between a sprint and super kart is the Wing which seems great…more down force… but doesn’t the wing keep the inside wheel down? In sprint karts a lot of the changes to handling are made in order to get that inside wheel up. Every other vehicle with aero has a Diff so how does the wing effect the handling?

     

    Again sorry if I’m a bit naïve here but I’ve got the kind of mind that always wonders until I find an answer. I’ve got a lot of the actual stuff that matters figured out so now I’m left to ponder. I would love to get a chassis set up with a cr500 because I’ve been fascinated with this motor and I’m a MUCH better driver than moto crosser so this would really be the only way to hear that thing scream. Thanks in advance!

    " Turd Ferguson is real and he will pass your a** "

    #61120

    Mark Traylor
    Participant

    I have been away from superkarts for quite a while so some of my answers may be outdated.

    1) CR500 isn’t legal.   2T engines limited to 250cc, 4T to 450cc.   Also we ran Rotax 257 singles, these engines produced in legal form for Formula ICE  (OE components except for a couple approved parts) 65hp to the wheel and they had a 6 speed transmission, the CR500 is only a 5 speed and doesn’t make a lot more power in a legal form.

    2)  Gas Gas is great but not legal in ICE, you have to run it in unlimited and you will be racing against the twins at 105hp BRC and PVP engines.

    3) We typically ran the wing at 0 angle of attack or a little negative in ICE.  handling is quite a lot different in my experience, run the rear narrow, no or very little ackerman,  more about rolling speed.  A slow turn is 65mph.  There is really a lot less chassis tuning going on.

    #61379

    Ben Lewis
    Participant

    Thanks for the quick reply

    I know the cr500 isn’t legal but the yz125 isn’t legal in Stock moto. Doesn’t mean its not a great or even better engine. However, I don’t know if Honda has a spec deal in super karts like in Sprint.

    But, a tuned cr500 can make almost 80hp on alcohol and probably twice the torque of a 250 so it still seems like it would be a good step in between the 250 single and double.

    I didn’t know the 257 was making those numbers. Quite impressive actually. Is there a good supply of parts in America to support the 257? I’ve done some looking and parts are out there but seem to be spares every one is getting rid of… makes me wonder if that formula is dead or dying.

    Makes sense on the wing. There aren’t nearly as many tight slow speed turns on a road course. And with little to no Ackerman the lifting effect would be reduced anyways.

    Anybody else currently racing have input?

     

     

    " Turd Ferguson is real and he will pass your a** "

    #61470

    Mark Traylor
    Participant

    Some guys still run the 257 but parts are a bit scarce.   My buddy runs an Anderson with a 257 and still runs up front anytime he races.  It is still the best powerplant in singles outside of parts cost and availability.  It is better in performance than the CR 250.  The Formula ICE class (single cylinder) can use any 250cc 2 stroke motocross based engine.  It is pretty open but you are restricted in displacement, OEM parts and running gasoline.  We ran a modified 40mm delorto carb.

    the CR500 is a moot deal.  Might be cool to use but it still isnt legal to run (based on displacement, not brand).  Comparing a modified CR500 on alcohol is not a valid comparison to an engine half the displacement, on gasoline and using all OEM parts.   Honda does not have a spec deal in superkarts, run what ever brand you want.  The honda is just common.   Eddie Lawson ran TZ250’s at about 105-110hp.  Others ran BRC, Hemmingway, or PVP in the twins.

    Gas Gas ix not MX based so it runs in unlimited with the twins.

    #61561

    DENNIS CRITCHLEY
    Participant

    Regarding the Rotax 257

    Parts for these motors are still available new & used except for the non pwr cylinders.  One can buy good used parts on ebay for these motors and if you are serious you can also buy good tuned motors for karts. Guys in the sport do sell used motors depending on the requirement, pipe/carb /ign which can be purchased at a decent price. If you are serious about a 257 motor i know of 3 brand new non pwr  plus 2 as new non-pwr valve for sale. No tire kickers please.

    Hope this helps and yes i run Rotax 257s, have for years and I do have new and used parts in stock

    Dennis

     

     

     

     

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    #61877

    Bobby Butler
    Participant

    As far as I know, WKA does not have a 250 twin class which would include 2 stroke 250 or 4 stroke engines.  They do have a unlimited class mostly lay downs. They have in the past resorted to a local option class and utilized a USSK rules set from long ago.  In which, the 4 strokes were allowed 500cc displacement.  I remember this because I still have a Yamaha YFZ built to 500cc in a Nemesis Superkart chassis that ran at such events. I hope this helps your thought process because the 4 stroke engine is better suited for most tracks except the longer ones like Daytona. They are really torque monsters, not mentioning the electric start.

    #61906

    Mark Traylor
    Participant

    IKF allows 250 twins two strokes

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