Top speed battle, Kart or Bike?

[karl]

Ive dun thunk up this conundrum , looking to build a ride that can achieve
at least 50mph with limited power, and cruise comfortably at 40mph for long distance travel.

Lets say the powerplant is a light n small 2-cycle, what would be the best bet?

At what point is the weight savings of a mini bike negated by aerodynamic drag?

Is it feasible that a heavier kart with the same power plant could achieve a higher top
speed than a mini bike?

I know there are lots of variables , but barebones low kart VS bike with similar tires,
whatcha think would win?

Thanks for reading.

 

[OPmini]

I'm biased in favor of mini bikes, so take this with a giant grain of salt.

If you built a low-down, narrow framed bike out of aluminum with body panels in the right place you could become very light and aerodynamic. Combine that with a small 250 or 125 two-stroke and you have a fast bike!

You could do something similar with a kart, but you would still need more materials (adding to the weight) to properly construct the kart.

And yes a heavier kart could go faster than a minibike with the same power plant could go faster, simply by changing sprocket gear ratios, but you'd be sacrificing torque.

 

[karl]

Thanks for the input. Aluminum is a bit out of my reach, but would be cool
to add fairings and such to make a bike more aerodynamic.

Im talking with ideal gear ratios, limited by engine power. What will win?

If only....

 

[madprofessor]

I've snatched a few of those out of coral tunnels off S. Florida (Florida Spiny, not Maines like pic). They only look fast on paper, not very speedy in real life. Your speedy ride could use a gimmick as clever as theirs is................They share their holes with green moray eels. Had one surprise me and take my mask off.

 

[JTSpeedDemon]

I think y'all are overlooking one factor a bit and that's rider comfort. Karl mentioned long distance travel, and I can't imagine that being terribly comfortable on a minibike built lightweight to go 50 MPH. Hit some big enough bumps and things could get pretty sketchy.
Now a kart on the other hand, you can just kind of sit back and cruise, and they can generally take more bumps without getting too squirrelly. Do note I'm assuming the minibike also has no or minimal suspension.
Granted I haven't ridden very many minibikes, but from what I've experienced, I'd take a kart over a bike any day for high speed and long distance.

 

[madprofessor]

See the pictures? "DragginBallz" was purpose-built to maim or kill anybody stupid enough to throw their leg over it. My first 212 hotrodding effort, 12 hp. with a CVT, too terrifying to speed test, best guess 65mph. Fully functional custom monoshock Springer front end, but rigid rear end. Rear shocks there are made for the seat, so there's your comfort consideration on a minibike. Was sold as a death machine with all liability waived, but at least I installed a new First Aid Kit where a headlight would ordinarily go. People may have their own reasons to long-ride a minibike, and those reasons may ignore comfort, not to mention ignoring dying in a blaze of glory. Aqui esta a los insectos en los dientes!
Here's to bugs in your teeth!

 

[karl]

I've snatched a few of those out of coral tunnels off S. Florida (Florida Spiny, not Maines like pic). They only look fast on paper, not very speedy in real life. Your speedy ride could use a gimmick as clever as theirs is................They share their holes with green moray eels. Had one surprise me and take my mask off.

Sweet! Im way too chicken to go diving, land dwelling creature. Id have a heart attack if one tore off my mask!

I'm more of a minimalist towards my builds, raw function. But ill keep you in mind and try to add something creative and original.

I think y'all are overlooking one factor a bit and that's rider comfort. Karl mentioned long distance travel, and I can't imagine that being terribly comfortable on a minibike built lightweight to go 50 MPH. Hit some big enough bumps and things could get pretty sketchy.

I will admit, I have broke 50 on a tiny azusa bike with 5in rims, and billet high compression 212 , 18hp? , no suspension or brakes. After riding
a few miles your almost exhausted. It could go faster but I never cared to gear it to do so, as I want to live somewhat

And most of my riding is done on are poorly maintained rural roads, so that must be a factor.

So I think a kart it shall be, $160 smackers + OH tax later I have committed to a set of four
DOT rated trailer wheels, 16in tall with 4 on 4 pattern. I have the rear hubs and axle, just need some
front hubs. And rotor for the disk brake

Should be a nice counterpart to my yard kart that is geared short, but steers with the gas pedal.

 

[madprofessor]

steers with the gas pedal.

Awesome! Thought only me and my other insane friends from back in the good ole daze called it steering with the pedal! Sideways and spinnin' 'em, or you're just a waste of gas!
EDIT: We were doing it with cars, not karts. State capitol of Tallacrashee, Florida back in the '70's.